GIFT  OF 
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LIBRARY 


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BACTERIA. 


BY 

GEORGE  M.  STERNBERG,  M.D.,  F.R.M.S., 

MAJOR  AND  SURGEON  0.  S.  ARMY  ;    MEMBER  OP  THE  BIOLOGICAL  SOCIETY  OF  WASHINGTON  ; 

LATE  MEMBER  OP  THE  HAVANA  YELLOW  FEVER  COMMISSION  OF  THE  NATIONAL  BOA&D 

OF  HEALTH;   CORRESPONDING  MEMBER  OF  THE  EPIDEMIOLOGICAL 

SOCIETY  OF  LONDON ;    ETC. 


Enclutung  One  J^untiretJ  anfc  JFift2=tfcj0 

FROM 

THE  WORK  OF  DR.  ANTOINE  MAGNIN, 

TRANSLATED  FROM  THE  FRENCH  IN  1880. 


ILLUSTRATED    BY    PHOTO-MICROGRAPHS,    ETC. 
Jen  Plates  and  Twenty-nine  Cuts, 


SECOND  EDITION. 


NEW  YORK: 

WILLIAM   WOOD    AND    COMPANY, 

66  AND  58  LAFAYETTE  PLACE. 

1884. 


Copyright,  1880, 
BY  GEORGE  M.  STERNBERG. 

Copyright,  1888, 
BY  GEORGE  M.  STERNBERG. 


fliULUCiY 
LIBRARY 


I-IMNTED    BY    JOHN    WILSON    AND    SON, 
IMVERSITY    PRESS. 


PREFACE  TO  SECOND  EDITION. 


THE  First  Edition  of  "  Bacteria "  being  nearly  ex- 
hausted at  the  end  of  six  months  from  date  of  publica- 
tion, the  writer  has  taken  advantage  of  the  opportunity 
which  this  favorable  reception  of  the  work  hac  given 
him,  and  has  revised  and  added  to  the  text,  with  a  view 
to  making  it  still  more  worthy  of  a  place  in  the  libraries 
of  physicians,  and  of  others  interested  in  this  important 
field  of  investigation.  Several  of  the  plates  have  also 
been  remodelled,  and  new  photo-micrographs  introduced 
in  place  of  some  of  those  in  the  first  edition,  which  have 
been  excelled  by  later  efforts.  The  bibliography  has 
also  been  brought  up  to  date. 

It  has  been  thought  best  in  the  present  edition  to 
remove  the  name  of  Dr.  Magnin  from  the  foremost 
place  upon  the  titlepage,  inasmuch  as  the  present  writer 
has  contributed  more  than  two-thirds  of  the  text,  and  as 
the  illustrations  from  nature  —  photo-micrographs  —  are 
all  his  work.  The  appreciation  in  which  Dr.  Magnin's 
systematic  account  of  the  bacteria  is  held  is  shown, 
however,  by  the  fact  that  we  have  not  attempted  to 
re-write  this  portion  of  the  work,  at  the  head  of  which 
a  separate  titlepage,  bearing  Dr.  Magnin's  name,  will 
be  found. 

JOHNS  HOPKINS  UNIVERSITY, 

BALTIMORE,  MD.,  July  28, 1884.  « 

M123312 


PREFACE. 


THE  work  of  Dr.  Magnin,  which  was  published  in 
Paris  in  1878  and  translated  by  the  writer  in  1880, 
gave  an  admirable  resume  of  our  knowledge  of  the  Bac- 
teria at  the  date  of  its  publication.  But  very  consid- 
erable progress  has  been  made  since,  especially  as 
regards  methods  of  manipulation,  the  comparative  value 
of  various  chemical  reagents  as  "  germicides  "  and  anti- 
septics, and  the  role  of  the  Bacteria  in  infectious  dis- 
eases. With  a  view  to  keeping  the  work  fully  up  to 
the  progress  of  science  in'  this  direction,  the  writer 
has  added  a  chapter  upon  each  of  these  subjects, 
and  one  upon  "  Bacteria  in  Surgical  Lesions "  (Parts 
Third,  Fourth,  Fifth,  and  Sixth).  His  name,  therefore, 
appears  upon  the  titlepage  as  one  of  the  authors  of  the 
present  volume.  It  has  not  been  considered  necessary, 
however,  to  rewrite  the  chapters  on  Morphology  and 
Physiology  (Parts  First  and  Second).  It  is  true  that 
the  classification  of  Cohn,  which  was  very  properly 
adopted  by  Professor  Magnin,  is  only  provisional,  and 
that  certain  recently  discovered  pathogenic  species  are 
not  included.  But  these  will  receive  attention  in  Part 
Fifth  of  the  present  volume ;  and  it  would  be  pre- 
mature to  attempt  a  natural  and  permanent  classifica- 
tion of  these  minute  plants,  which  are  now  engaging 
the  attention  of  numerous  investigators*  in  all  parts  of 


VI  PREFACE. 

the  civilized  world.  For  the  present  we  probably  can- 
not do  better  than  to  adhere  to  the  artificial  classifica- 
tion, based  upon  morphological  characters  alone,  which 
Cohn  has  given  us. 

It  must  be  remembered,  however,  that  SPHERO- 
BACTERIA  —  micrococci  —  are  not  always  round;  that 
there  is  no  well-defined  line  of  demarcation  between 
the  MICRO-BACTERIA  and  the  DESMO-BACTERIA,  between 
the  genus  BACTERIUM  and  the  genus  BACILLUS,  or  be- 
tween the  last-named  genus  and  the  LEPTOTHRIX. 

The  systematic  naturalist,  in  his  attempt  to  establish 
genera  and  species  among  these  lowly  organisms,  meets 
with  difficulties  even  greater  than  those  encountered  in 
the  classification  of  the  higher  cryptogams  and  flower- 
ing plants.  These  difficulties  arise  from  the  multitude 
of  species  and  minute  size  of  the  unicellular  organisms 
under  consideration ;  from  the  various  phases  which 
the  same  species  may  present  at  different  epochs  in 
the  life-history  of  the  plant ;  from  the  morphological 
identity  of  species  having  different  physiological  char- 
acters ;  and,  finally,  from  the  influence  of  the  environ- 
ment in  modifying  both  morphological  and  physiological 
characters. 

Most  writers  continue  to  speak  of  the  Bacteria  as 
fungi.  The  observations  of  the  writer  are,  however, 
in  favor  of  the  view  of  Cohn,  that  they  are  more  nearly 
related  to  the  algae.  It  would  be  idle,  however,  to 
discuss  this  question,  as  the  border-line  of  these  two 
great  classes  of  the  VEGETABLE  KINGDOM  is  not  well 
defined ;  and  here,  as  in  the  attempt  to  establish  gen- 
era and  species,  the  systematic  naturalist  must  ever 
encounter  the  stubborn  fact  that  NATURE  is  contin- 
uous, and,  consequently,  that  ell  attempts  at  classifi- 
cation are  artificial. 

The  writer  ventures  to  hope  that  the  rtsumt  given  in 
the  present  volume  will  be  found  to  fairly  represent  the 


PREFACE.  vii 

present  state  of  science  as  regards  the  minute  organ- 
isms of  which  it  treats.  No  doubt  the  book  contains 
much  that  will  not  bear  rigid  scientific  crijticism  ;  and 
the  constant  additions  to  our  knowledge  which  are 
daily  being  made  will  necessitate  frequent  revisions  and 
additions,  if  a  favorable  reception  by  the  Medical  Pro- 
fession, and  students  of  Biology,  makes  it  practicable 
for  the  writer  to  carry  out  his  present  intention  of  rep- 
resenting in  future  editions  the  progress  which  may  be 
made  in  the  interval.  I  am  not  prepared  to  say,  how- 
ever, that  the  heliotype  plates  which  illustrate  this 
edition  will  appear  in  subsequent  editions,  if  they  are 
called  for.  These  plates  add  greatly  to  the  cost  of  the 
volume,  and  they  will  perhaps  be  less  satisfactory  than 
lithographs  or  wood-cuts  to  those  not  accustomed  to 
similar  views  under  the  microscope,  and  to  those  critics 
who  are  not  familiar  with  the  technical  difficulties 
attending  an  attempt  to  photograph  the  minute  organ- 
isms here  represented.  If  the  clean  field  and  sharply- 
drawn  outlines  which  it  is  so  easy  to  draw  upon  wood 
or  stone  makes  a  prettier  picture,  and  one  which  may 
be  preferred  by  some,  there  can  be  no  doubt  that  these 
views  from  nature,  if  closely  studied,  are  more  instruc- 
tive than  drawings,  notwithstanding  the  inevitable  de- 
fects arising  in  some  instances  from  the  presence  in  the 
field  of  view  of  extraneous  objects,  and  from  the  im- 
possibility of  having  every  part  of  the  field  in  the  best 
possible  focus  at  the  same  time  in  these  photo-micro- 
graphs, which  are  made  with  objectives  of  high  power 
having  an  extremely  limited  focal  range. 

G.  M.  S. 

FORT  MASON,  SAN  FRANCISCO, 
August  15, 1883. 


TABLE    OF    CONTENTS. 


PAGE 

INTRODUCTION 11 

HISTORICAL  .       13 


PART    FIRST. 

MORPHOLOGY    OF    THE    BACTERIA. 
CHAPTER  I.  — ORGANIZATION. 

1.  —  OF  THE  BACTERIA  IN  GENERAL 28 

Forms 28 

Dimensions 29 

Colors 31 

Movements 32 

Structure 35 

Cell-Membrane 35 

Protoplasm 36 

Cilia 39 

2.  —  DIFFERENT  MODES  OF  ASSOCIATION 43 

Form  of  Little  Chain  (Torula) .  43 

Form  of  Zooyl&a 44 

Form  of  Mycoderma,  &c 45 

CHAPTER  II.  —  CLASSIFICATION  AND  DESCRIPTION. 

1. — PLACE  OF  THE  BACTERIA 48 

Among  Organized  Beings 53 

In  the  Vegetable  Kingdom 55 

2.  —  CLASSIFICATION 59 

Characters  Generic  and  Specific 60 

Classification  of  Cohn .  .  65 


TABLE  OF  CONTENTS. 

PAGE 

3.  —  DESCRIPTION  OF  GENERA  AND  SPECIES      ....  65 

Spherobacteria 71 

Micrococcus 72 

Monads 78 

Microbacteria 80 

Bacterium 80 

Desmobacteria 86 

Bacillus 87 

Leptothrix 90 

Spirobacteria 91 

Vibrio 92 

Spirillum 94 


PART   SECOND. 

PHYSIOLOGY    OF    THE    BACTERIA. 
CHAPTER  I.  — DEVELOPMENT  IN  GENERAL. 

§'  1.  — ORIGIN  OF  BACTERIA 101 

Heterogenesis 102 

Dissemination 103 

In  Air 103 

In  Water 106 

In  the  Human  Organism 107 

§2. — NUTRITION  AND  RESPIRATION Ill 

Aliments  :  Water Ill 

Nitrogen 112 

Carbon 113 

Oxygen 115 

Temperature 118 

Other  Agents 121 

§  3.  —  REPRODUCTION 123 

Fission 123 

Spores 126 

Sjiorangia 130 

Polymorphism 133 


TABLE  OF  CONTENTS.  XI 

CHAPTER  II.  —  DEVELOPMENT  IN  DIFFERENT  MEDIA. 

PAGE 

§  1.  —  ROLE  OF  BACTERIA  IN  FERMENTATIONS    ....  137 

Acetic  Fermentation 139 

Arnmoniacal  Fermentation 142 

Lactic  and  Butyric  Fermentation 144 

§  2.  —  ROLE  IN  PUTREFACTION  AND  NITRIFICATION     .     .  148 


PART    THIRD. 

TECHNOLOGY. 

§  1.  —  METHODS  OF  CULTIVATION 156 

Methods  of  obtaining  Pure  Stock 156 

Natural  Culture-Fluids 161 

Blood 161 

Milk* 163 

Urine 164 

Aqueous  Humor 165 

Artificial  Culture-Fluids 167 

Sterilization  of  Culture-Fluids 168 

Culture  Tubes  and  Flasks 171 

Culture  Flasks  used  by  the  Author 175 

Culture  Oven 180 

Thermostat  for  Gas 181 

§  2.  —  THE  RECOGNITION  OF  BACTERIA 184 

§  3.  —  STAINING  BACTERIA 186 

Staining  the  Tubercle  Bacillus 190 

Baumgarten's  Method 191 

Ehrlich's  Method 191 

Gibbs'  Method 192 

§  4.  —  PHOTOGRAPHING  BACTERIA 194 

§  5.  —  COLLECTION  OF  ATMOSPHERIC  BACTERIA  ....  197 

Examination  of  Water 201 

§  6.  —  ATTENUATION  OF  VIRUS       201 

Method  of  Pasteur  .                                        .  202 


TABLE  OF  CONTENTS. 

PAGE 

Method  of  Toussaint 204 

Method  of  Chauveau 205 

Method  by  Intravenous  Injection 206 

Attenuation  of  Virus  by  Chemical  Reagents     .     .  206 


PART    FOURTH. 

GERMICIDES  AND  ANTISEPTICS. 

Acetic  Acid 215 

Alcohol 215 

Aluminium  Acetate 216 

Aluminium  Chloride 216 

Ammonia 216 

Aromatic  Products  of  Decomposition 216 

Arsenious  Acid 216 

Benzoic  Acid 217 

Boric  Acid 217 

Bromine 218 

Camphor 218 

Carbonic  Acid 218 

Carbonic  Oxide 219 

Carbolic  Acid 219 

Chloral  Hydrate 220 

Chloroform 220 

Chlorine 220 

Chromic  Acid 221 

Citric  Acid 221 

Creosote 222 

Cupric  Sulphate 222 

Ether 222 

Eucalyptol 222 

Ferric  Sulphate 222 

Ferri  Chloridi  Tinct 223 

Glycerine 223 

Heat 223 

Hydrochloric  Acid 'JiM 

Hydrogen 225 

Iodine 225 

Mercuric  Bichloride  225 


TABLE  OF  CONTENTS.  xiii 

PAGE 

Nitric  Acid 226 

Nitrous  Acid 226 

Oil  of  Mustard .     .  226 

Oil  of  Turpentine 226 

Osmic  Acid 226 

Oxalic  Acid 226 

Ozone 227 

Oxygen 227 

Picric  Acid 227 

Potash 227 

Potassium  Arsenite 228 

Potassium  Chlorate 228 

Potassium  Iodide 228 

Potassium  Nitrate 228 

Potassium  Permanganate 228 

Pyrogallic  Acid 229 

Pyroligneous  Acid 229 

Quinine 229 

Salicylic  Acid 229 

Soda 230 

Sodium  Biborate 231 

Sodium  Chloride 231 

Sodium  Hyposulphite 232 

Sodium  Sulphite 232 

Sodium  Salicylute 232 

Sulphuric  Acid 233 

Sulphurous  Acid 233 

Sulphuretted  Hydrogen 234 

Tannic  Acid 234 

Thymol 234 

Zinc  Chloride 234 

Zinc  Sulphate 235 


PART    FIFTH. 

BACTERIA  IN  INFECTIOUS  DISEASES. 

Anthrax 265 

Symptomatic  Anthrax 280 

Cerebro- Spinal  Meningitis 284 


XIV  TABLE  OF  CONTENTS. 

PAGE 

Cholera 285 

Erysipelas 286 

Cholera  of  Fowls 288 

Diphtheria 291 

Disease  produced  by  Bacilli 297 

Fatal  Epidemic  among  Fish  caused  by  Bacteria 299 

Glanders 299 

Gonorrhoea 301 

Hydrophobia 314 

Intermittent  Fever 317 

Leprosy 331 

Malignant  (Edema 336 

Milk  Sickness 339 

Measles 340 

Pleuro-Pneumonia 341 

Infectious  Pneumonia 342 

Pyaemia  in  Rabbits 343 

Relapsing  Fever 346 

Scarlet  Fever 349 

Septicaemia  in  Mice 351 

Septicaemia  in  Rabbits 355 

Spreading  Abscess  in  Rabbits .  376 

Swine  Plague 378 

Syphilis 380 

Tuberculosis 384 

Typhoid  Fever 400 

Ulcerative  Endocarditis 411 

Variola 411 

Variola  of  Pigeons 413 

Whooping  Cough 415 

Yellow  Fever    ,  417 


PART    SIXTH. 

BACTERIA  IN  SURGICAL  LESIONS  ,    442 


BIBLIOGRAPHY 457 

INDEX  489 


PEEFACE  BY  TRANSLATOR 


HAVING  found  the  admirable  resumS  of  our  knowl- 
edge of  the  bacteria,  by  Dr.  Magnin,  of  great  assistance 
to  me,  in  pursuing  the  investigations  in  which  I  have 
been  engaged  during  the  past  year  under  the  auspices 
of  the  National  Board  of  Health,  it  has  seemed  to  me 
that  a  translation  of  the  work  into  English  and  its  publi- 
cation in  this  country  would  be  productive  of  good  in 
more  ways  than  one,  and  of  the  advancement  of  science. 
To  the  naturalist,  it  cannot  fail  to  be  of  value,  as  the 
most  approved  classification,  that  of  Cohn,  is  given, 
with  a  full  description  of  species.  To  give  additional 
value  to  this  portion  of  the  work,  figures  of  many  of  the 
best-known  forms,  drawn  from  various  foreign  sources, 
and  reproductions  of  some  of  my  own  photo-micro- 
graphs (by  permission  of  the  National  Board  of  Health), 
have  been  introduced. 

If  we  are  to  judge  from  the  scanty  literature  of  the 
subject  in  this  country,  the  amount  of  interest  which 
has  been  aroused  by  the  revelation  of  a  new  world  of 
micro-organisms,  and  by  the  momentous  questions  which 
have  been  raised  in  connection  with  them,  is  far  below 
that  awakened  in  Germany,  France,  and  England.  This 
is  not,  however,  really  the  case  ;  for,  while  we  have  but 
few  active  workers  in  the  difficult  fields  of  inquiry 


XVI  PREFACE   BY   TRANSLATOR. 

which  have  proved  so  attractive,  especially  for  the  Ger- 
man and  the  French  savants,  there  is  nevertheless  a 
wide-spread  interest  in  these  investigations,  and  a  desire 
to  know  their  results.  But,  just  here,  we  are  met  with 
a  difficulty  which  has  no  doubt  discouraged  many,  and 
perhaps  caused  some  to  drop  the  whole  subject  in  dis- 
gust. The  results  have  been  so  contradictory,  and  so 
many  would-be  savants  have  uttered  opinions  entirely 
opposed  the  one  to  the  other,  that  we  find  it  impossible 
to  arrive  at  any  definite  opinion,  not  knowing  whom  to 
believe.  This  being  the  condition  of  affairs,  it  seems  to 
me  that  it  is  necessary  for  us  to  commence  investigating 
for  ourselves,  —  first  making  ourselves  familiar  with  what 
has  been  done  abroad,  and  then  avoiding,  if  possible,  the 
quicksands  into  which  unfortunate  science  has  too  often 
been  dragged  by  her  votaries.  One  great  trouble 
which  we  have  experienced  in  this  country  is  in  judg- 
ing of  the  comparative  value  of  the  observations  of  dif- 
ferent men  who  are  equally  unknown  to  us.  A  very 
plausible  article  may  be  written  by  a  very  careless 
observer ;  or  a  very  cautious  observer  may  fail  to  give 
confidence  in  his  results,  because  of  a  certain  degree  of 
confusion  in  his  language.  When  experiments  are  well 
devised,  carefully  executed,  and  described  with  preci- 
sion, as  is  done  by  such  men  as  Pasteur  and  Tyndall,  we 
cannot  fail  to  attach  great  weight  to  the  conclusions 
reached.  And  when  so  accomplished  a  microscopist  as 
Cohn  or  Koch  asserts  that  he  has  seen  such  and  such  a 
thing,  or  has  made  such  and  such  measurements,  we 
cannot  doubt  the  reliability  of  the  observation.  But 
sometimes  we  are  deceived  by  giving  credence  to  a  man 
who  has  achieved  reputation  in  one  line  of  study,  but  of 


PREFACE  BY  TRANSLATOR.         XV11 

whose  skill  and  training  in  the  use  of  the  microscope  we 
have  no  means  of  judging.  Such  a  man  may  be  a  great 
surgeon,  or  a  great  clinician,  or  a  great  chemist,  and  yet 
be  a  mere  tyro  with  the  microscope.  When,  then,  we 
see  it  announced  that  Dr.  So-and-so  failed  to  discover 
any  micrococci  in  pus,  in  blood,  or  what  -not,  taken  from 
a  certain  source,  we  are  justified  in  asking,  —  first,  what 
power  did  the  learned  doctor  use  ?  second,  is  he  capa- 
ble of  distinguishing  micrococci  in  fluids  which  contain 
them  beyond  question?  Or,  if  he  does  discover  them, 
we  may  ask  if  he  is  accustomed  to  making  a  differential 
diagnosis  between  micrococci  and  inorganic  granular 
material,  or  unorganized  granules  of  organic  origin. 
This  is  a  decision  which  the  most  accomplished  micro- 
scopist  is  sometimes  unable  to  make,  except  by  the  aid 
of  chemical  tests  and  culture  experiments. 

To  avoid  this  want  of  confidence  in  results,  which  has 
naturally  grown  out  of  carelessly  made  observations  and 
contradictory  statements,  it  is  desirable  that  full  and 
minute  details  should  be  given  of  all  observations  and 
experiments  made,  and,  whenever  possible,  that  photo- 
micrographs should  be  made  of  all  micro-organisms 
described,  or  of  a  thin  stratum  of  a  liquid  asserted  not 
to  contain  any ;  as,  when  a  sufficiently  high  power  is 
used,  this  settles  the  question  of  their  presence  or 
absence,  beyond  dispute,  and  enables  other  students  to 
make  comparisons  and  measurements  which  cannot  fail 
to  promote  the  interests  of  true  science. 

The  National  Board  of  Health  of  the  United  States 
has  the  credit  of  first  adopting  this  method  of  recording 
the  results  of  scientific  investigation,  in  this  direction, 
as  a  constant  and  unimpeachable  record  of  what  has 


XV111  PREFACE  BY  TRANSLATOR. 

r 

been  seen  by  the  investigator.  The  commission  sent  to 
Havana  last  summer  for  the  investigation  of  j^ellow 
fever,  was  instructed  to  pursue  this  method,  and  was 
accompanied  by  a  photographer  and  supplied  with  all 
the  necessary  appliances  for  carrying  these  instructions 
into  effect. 

The  superficial  reader  may  find  much  to  criticise  in 
the  work  of  Dr.  Magnin,  but  I  am  convinced  that 
those  who  read  it  carefully  cannot  fail  to  be  pleased 
with  the  truly  scientific  spirit  in  which  it  is  written ; 
the  fairness  with  which  conflicting  opinions  are  stated  ; 
the  caution  manifested  as  to  the  drawing  of  definite 
conclusions  where  questions  are  still  under  discussion  ; 
and,  above  all,  the  extent  of  his  literary  researches  and 
the  systematic  way  in  which  he  has  arranged  the  re- 
sults. 

For  the  naturalist,  for  the  physician,  or  for  the  non- 
professional  man  of  general  culture,  who  desires  to  have 
accessible  in  a  condensed  form  the  most  important  re- 
sults achieved  in  this  line  of  inquiry  up  to  the  present 
day,  this  volume  cannot  fail  to  be  of  value  ;  while  for 
the  student  and  the  investigator  in  search  of  fuller 
information,  the  summary  given  of  the  labors  of  nu- 
merous individuals,  together  with  the  copious  bibliog- 
raphy, which  I  have  brought  up  to  date,  will  doubtless 
be  of  service.  Believing  this  to  be  true,  it  has  been  a 
pleasure  for  me  to  devote  a  portion  of  my  summer  vaca- 
tion to  the  translation  of  this  little  volume. 

G.  M.  S. 
SALEM,  MASS.,  August  1,  1880. 


LIST  OF  PLATES. 


PLATE  PAGE 

I.     The  Cilia  of  B.  termo  and  S.  voluntans.     (Drysdale 

and  Dallinger) 40 

II.     Different  Modes  of  Grouping  of  the  Bacteria.    (Photo- 
micrographs by  Dr.  Stern  berg) 17 

III.  Bacilli  and  Spores.     (Photo-micrographs  by  Dr.  Stern- 

berg)       58 

IV.  Disease-Ferments  of  Wort  and  Beer.    (Pasteur)  .     .  84 
V.     Different  Forms  of  Bacteria.     (Cohn) 95 

VI.     Micrococci.     (Photo-micrographs  by  Dr.  Sternberg)  127 

VII.     Pathogenic  Bacilli 264 

VIII.     Bacillus  anthracis.    (Photo-micrographs  by  Dr.  Stern- 
berg)    272 

IX.     Bacillus  tuberculosis.     (Chromo-lithograph)  ....  396 

X.  •    Blood  of  Yellow  Fever  Patients.     (Photo- micrographs 

by  Dr.  Sternberg) 421 


INTRODUCTION. 


PART    FIRST. 

MOEPHOLOGY  OF  THE  BACTERIA. 

PART    SECOND. 

PHYSIOLOGY  OF  THE  BACTERIA. 

BY 

DR.   ANTOINE   MAGNIN, 

LICENTIATE  OF  NATURAL  SCIENCES;  CHIEF  OF  THE  PRACTICAL  LABORS  IK  NATURAL 

HISTORY  TO  THE  FACULTY  OF  MEDICINE  OF  LYONS;  LAUREATE  OF  THE  FACULTY 

OP  MEDICINE  OF  PARIS  (SILVER  MEDAL,  1876);  GENERAL  SECRETARY 

OF  THE  BOTANICAL  SOCIETY  OF  LYONS;  MEMBER  OF  THE 

BOTANICAL  SOCIETY  OF  FRANCE;  ETC. 

TRANSLATED  FROM  THE  FRENCH 
BY  DR.   GEORGE  M.   STERNBERG. 


THE     BACTERIA. 


INTRODUCTION. 

"  Corruptio  unius  est  generatio  al  terms." 

LUCRETIUS,  De  Rerun,  Natura. 

OF  all  the  studies  which  have  for  their  object 
the  inferior  organisms,  those  which  relate  to  the 
bacteria  offer,  without  contradiction,  the  greatest 
interest,  as  they  touch  the  most  diverse  problems, 
which,  it  is  true,  are  the  most  difficult  and  the 
least  known  in  biology.  The  history  of  these  mi- 
nute organisms  is,  in  truth,  related  to  that  of 
spontaneous  generation,  to  that  of  the  fermenta- 
tions, to  the  pathogeny  and  therapeutics  of  a  great 
number  of  virulent  and  contagious  affections,  and, 
in  a  more  general  manner,  to  all  the  unknown 
which,  notwithstanding  the  efforts  of  modern  sci- 
ence, still  surrounds  the  origin  of  life  and  its  pres- 
ervation. 

If  the  relation  of  these  inferior  organisms  to 
the  origin  of  living  beings  is  yet  obscure,  their 
role  in  the  preservation  of  life  is  better  known. 
It  is  known  that  organic  matter,  once  produced 
and  become  solid,  so  to  speak,  cannot  again  enter 
into  the  general  current  until  it  has  undergone 


12  THE  BACTERIA. 

new  transformations,  metamorphoses  produced,  ac- 
cording to  some  savants,  favored,  according  to 
others,  but,  without  contradiction,  accompanied 
by  the  development  of  bacteria;1  and,  without 
wishing  to  attribute  to  these  organisms  a  finality 
which  is  repugnant  to  our  monistic  conception  of 
the  universe,  it  may  be  said  that  it  is  thanks  to 
them  that  the  continuation  of  life  is  possible  on 
the  surface  of  the  globe. 

But,  if  these  studies  are  full  of  interest,  their 
field  is  so  vast  that  we  cannot  flatter  ourselves 
that  we  have  passed  over  the  whole  of  it  with 
equal  care.  The  little  time  that  has  been  ac- 
corded us  for  the  composition  of  this  thesis  will 
be  our  excuse  for  the  inevitable  imperfections 
which  will  doubtless  be  found  in  our  work. 


1  The  bacteria :  such  is  the  subject  which  has  been  imposed  upon  us  ; 
but  it  is  certainly  useless  to  give  the  reasons  which  have  caused  us  to 
study  not  only  the  bacteria  properly  so  called,  taking  the  word  in  its 
most  restricted  sense,  but  all  the  organisms  which  are  comprised  under 
the  names  of  bacteria,  vibrios,  schizomyce'tes,  schizophytes,  etc. 


HISTOKICAL. 


THE  bacteria  are  the  lowest  organisms,  situated 
upon  the  limit  of  the  two  kingdoms,  animal  and 
vegetable,  and  are  thus  defined  by  the  botanists 
who  have  most  recently  occupied  themselves  with 
them :  — 

"  Cells  deprived  of  chlorophyll,  of  globular,  ob- 
long, or  cylindrical  form,  sometimes  sinuous  and 
twisted,  reproducing  themselves  exclusively  by 
transverse  division,1  living  isolated  or  in  cellular 
families,  and  having  affinities  which  approach  them 
to  the  algae  and  especially  to  the  oscillatoriae." 

But,  before  arriving  at  this  degree  of  relative 
precision,  the  history  of  the  bacteria  has  passed 
through  the  most  diverse  vicissitudes.  At  one 
time  considered  as  animals,  at  another  taken  for 
vegetables,  transported  from  the  algae  to  the  fungi, 
one  author  has  even  gone  so  far  as  to  refuse  to 
them  the  nature  of  living  beings.2  This  diversity 
of  opinions  is  due  to  the  minuteness  of  their  di- 
mensions and  the  difficulties  with  which  their  ob- 
servation is  surrounded. 

1  Reproduction  by  the  formation  of  endogenous  spores  also  occurs 
among  the  bacilli.     (See  plate  III.)  — G.  M.  S. 

2  Polotebnow. 


14  THE  BACTERIA. 

Although  an  historical  statement  of  the  progress 
of  our  knowledge  of  these  minute  organisms  has 
been  given  in  several  publications,  we  think  it  best 
to  make  here  a  new  historical  summary,  which  will 
be  completed  by  an  indication  of  the  principal  pa- 
pers relating  to  them  which  have  been  published 
recently. 

The  first  observer  who  perceived  bacteria  was 
Leeuwenhoeck.  As  early  as  1675,  while  examin- 
ing by  chance  with  his  magnifying  glasses  a  drop 
of  putrid  water,  the  father  of  microscopy  re- 
marked with  profound  astonishment  that  it  con- 
tained a  multitude  of  little  globules,  which  moved 
with  agility.  The  following  year  he  recognized 
the  presence  of  bacteria  in  faeces  and  in  tartar 
from  the  teeth ;  and,  if  he  has  not  named  them, 
it  is  easy  to  assure  one's  self  by  the  description 
which  he  has  given  of  their  form  and  of  their 
movements,  and  by  the  figures  which  accompany 
these  descriptions,1  that  the  organisms  observed 
by  him  are  truly  Bacteria,  Vibrios,  and  perhaps 
even  Leptothrix. 

In  1773  0.  F.  Muller  endeavored  to  classify 
these  organisms.  He  made  of  them  a  group  of 
infusoria,  under  the  name  of  Infusoria  crassius- 
cula,  and  established  two  genera,  —  the  g.  Monas 
and  Vibrio ;  the  first  characterized  as  follows : 
"  vermis  inconspicuus,  simplicissimus,  pellucidus, 
punctiformis,"  comprising  the  following  species: 
Monas  termo,  atomus,  punctum,  ocellus,  lens,  mica, 

1  Leeuwenhoeck.  Opera  omnia,  Lugd.  Batar.,  1722, 11,  p.  40,  fig.  A  to  G. 


HISTORICAL.  15 

trnnquiUa,  lamellula,  pulviscidus,  uva,  which  it 
is  impossible  to  identify  with  the  species  at  pres- 
ent recognized.  The  genus  Vibrio  "  vermis  incon- 
spicuus,  simplicissimus,  teres,  elongatus"  enclosing 
under  thirty-five  specific  names,  with  the  true 
bacteria,  some  organisms  belonging  to  other 
classes  of  the  animal  and  vegetable  kingdoms. 

In  the  classification  of  the  infusoria  given  by 
Bory  de  Saint-Vincent  in  the  "  Encyclopedic 
Methodique"  (1824)  and  afterwards  in  the  "  Dic- 
tionaire  Classique  d'Histoire  Naturelle"  (1830)  the 
bacteria  are  distributed  in  two  different  families 
of  the  microscopic  gymnodae,  the  monadaires  and 
the  vibrionides.  Besides  the  monads,  properly  so 
called,  of  which  the  Monas  termo  has  been  pre- 
served by  the  greater  part  of  the  bacterologists, 
the  monadaires  include  some  veritable  infusoria, 
which  have  no  relation  with  the  monads.  It  was 
the  same  with  the  vibrionides,  of  which  the  genera 
Vibrio  and  Mellanella  included  some  beings  very 
different  in  their  organization.  Indeed,  beside 
some  veritable  vibrios,  bacteria,  and  spirilla, 
constituting  the  genus  Mellanella,  Bory  placed 
some  nematoid  worms,  such  as  the  Anguillula 
of  vinegar. 

With  Ehrenberg  (1838)  and  Dujardin  (1841) 
the  family  of  the  vibrioniens  was  established  upon 
characters  more  homogeneous,  and  their  species 
upon  distinctions  truly  scientific.  But  these  two 
observers,  followed  in  this  by  M.  Davaine,  deny 
completely  the  affinities  of  the  elongated  bacteria 


16  .THE  BACTERIA. 

(Bacterium,  Vibrio^  etc.)  with  the  punctiform 
bacteria  ( Monas] ;  and  it  is  necessary  to  come 
to  the  time  of  MM.  Hallier,  Hoffmann,  Cohn,  and 
the  greater  number  of  recent  botanists,  in  order 
to  see  these  two  forms  brought  together  anew. 
In  fact,  Ehrenberg  defines  his  vibrioniens,  which 
he  arranges  between  the  volvocinece  and  the 
closteria  "  animals,  filiform,  distinctly  or  appar- 
ently polygastric,  no  mucous  membrane,  naked, 
without  external  organs,  with  the  body  (like  mon- 
ads) uniform  and  united  in  chains  or  filiform  se- 
ries, as  a  result  of  incomplete  division."  He 
included  in  this  class  all  filiform  bodies  gifted 
with  proper  movement  and  formed  of  articles, 
dividing  them  into  four  genera :  — 

1.  Bacterium:  filaments  linear  and  inflexible;  three 
species. 

2.  Vibrio :  filaments  linear,  snakelike,  flexible  ;  nine 
species. 

3.  Spirillum :  filaments  spiral,  inflexible ;  three  spe- 
cies. 

4.  SpirocTicete :  filaments  spiral,  flexible;  one  species. 

A  fifth  genus,  including  but  one  species,  the 
Spirodiscus  fulvus,  with  filaments  in  a  helix,  in- 
flexible, disposed  in  contiguous  layers,  has  not 
been  seen  since  Ehrenberg.  Let  us  add  that 
Ehrenberg  often  attributed  to  them  a  complex 
structure,  stomachs  more  or  less  numerous,  a  pro- 
boscis, cilia  serving  as  organs  of  locomotion,  — 
all  characters  that  more  recent  observers  have 
failed  to  find.  Nevertheless,  we  must  make  an 


HISTORICAL.  17 

exception  in  favor  of  the  cilia,  of  which  the  ex- 
istence has  been  recently  verified  in  the  case  of 
several  of  the  bacteria  by  divers  botanists,  among 
others  by  MM.  Cohn  and  Eug.  Warming. 

Dujardin  (1841),  in  his  "  Histoire  Naturelle  des 
Zoophytes/'  preserved  the  family  of  the  vibrioni- 
ens  of  Ehrenberg  among  the  infusoria,  characteriz- 
ing them  as  follows  :  "  filiform  animals,  extremely 
slender,  without  appreciable  organization,  without 
visible  locomotive  organs."  He  made  but  few 
modifications,  of  which  the  principal  consisted  in 
uniting  Spirochceta  with  Spirillum,  Dujardin.  Re- 
jecting the  character  that  Ehrenberg  drew  from 
the  rigidity  of  the  spirilla,  the  Spirochceta  pllca- 
t'dis,  Ehrb.  became  the  Spirillum  plicatile,  Duj. ; 
but,  as  will  be  seen  later,  this  change  has  not 
been  maintained.  Dujardin,  then,  classed  the  bac- 
teria in : 

1.  Bacterium :   filaments  rigid,  with  a  vacillating 
movement. 

2.  Vibrio:    filaments  flexible,  with  an  undulatory 
movement. 

3.  Spirillum :  filaments  spiral,  movement  rotatory. 

Until  this  time  the  bacteria  had  been  considered 
as  animals  placed  at  the  foot  of  the  series.  Sub- 
sequently the  tendency  to  place  them  in  the 
vegetable  kingdom  became  more  and  more  pro- 
nounced. 

Already,  since  1853,  M.  Ch.  Robin  had  pointed 
out  the  relationship  of  the  bacteria  and  of  the 

2 


18  THE   BACTERIA. 

vibrios  with  Leptothrix.  This  opinion,  which 
was  not  favorably  received  by  the  authors  who 
adopted  nearly  all  of  the  generic  groups  of  Ehren- 
berg  and  Dujardin,  is  to-day  accepted  by  many 
botanists,  above  all  since  the  labors  of  Cohn.  (See 
below:  classification.)  At  all  events,  it  is  to  M. 
Davaine  (1859)  that  we  are  indebted  for  clearly 
pointing  out  that  the  vibrioniens  are  vegetables, 
nearly  allied  to  the  algae,  and  especially  to  the 
confervas. 

This  same  author,  having  observed  some  mo- 
tionless bacteria,  thought  it  necessary  to  give 
this  character  great  consideration,  and  to  estab- 
lish a  fourth  group,  the  genus  Baeteridium,  which 
he  added  to  the  three  others  admitted  by  Dujar- 
din ;  but  in  this  creation  he  was  less  happy  than 
in  his  placing  the  vibrioniens  among  the  vege- 
tables ;  for  we  shall  see  further  on  that  this  char- 
acter of  mobility  or  of  immobility  is  not  absolute, 
and  that  it  depends  upon  the  age  of  the  bacterium 
or  upon  certain  conditions  relating  to  the  medium 
in  which  it  is  placed. 

The  most  recent  complete  exposition  of  the 
classification  and  of  the  ideas  of  M.  Davaine  is 
found  in  the  "  Dictionnaire  Encyclop.  des  Sci- 
ences M£dicales,"  art.  Bacteries  (1868).  It  may 
be  summed  up  as  follows :  — 


Filaments  straight 
or  bent,  but  not 
in  a  spiral  . 


Moving  sponta-)  Rigid.     .    BACTERIUM. 

neously  .     .  j  Flexible .    VIBRIO. 
Motionless  ....    BACTKKIDIUM. 


Filaments  spiral SPIRILLUM. 


HISTORICAL.  19 

The  genus  Bacterium  comprises  six  species, — 
S.  termo,  catenula,  punctum,  triloculare,  or  articula- 
tum,  already  described  by  Ehrenberg  and  Dujar- 
din,  and  B.  putredinis  and  capitatum,  new  species 
of  M.  Davaine,  established,  the  first  for  a  bacte- 
rium producing  rot  in  plants,  the  second  for  a  spe- 
cies, swollen  at  the  extremity,  observed  in  some 
macerations. 

The  genus  Vibrio  includes  twelve  species,  — 
V.  lineola,  tremulans,  rugula,  prolifer,  serpens, 
bacillus,  synxanthus,  and  syncyanus  of  previous 
authors  and  the  V.  lactic,  butyric,  and  tartaric 
right,  discovered  by  M.  Pasteur  in  these  different 
fermentations. 

In  the  genus  Bacteridium,  M.  Davaine  places 
five  new  species, — the  "  Bacteridies  charbonneuse, 
intestinale,  du  levain,  glair  euse,  et  des  infusions." 
He  includes  also  the  ferment  which,  according  to 
M.  Pasteur,  occasions  the  "  sickness  of  turned 


wine." 


Finally,  the  genus  Spirillum  includes  the  spe- 
cies S.  undula,  tenue,  volutans  of  Ehrenberg,  S. 
rufum  and  leucomcenum  of  Perty,  and  S.  plicatile, 
Duj. 

From  this  moment  the  history  of  the  bacteria 
enters  upon  a  new  phase.  The  labors  of  M.  Pas- 
teur upon  the  inferior  organisms  and  their  role  in 
fermentation,  the  researches  of  MM.  Davaine  and 
Hallier  upon  the  bacterium  of  charbon,  and  the 
micrococci  of  contagious  maladies,  call  the  atten- 
tion of  chemists  and  of  pathologists  to  these  or- 


20  THE  BACTERIA. 

ganisms  and  especially  to  the  bacteria.  Their 
origin,  their  evolution,  the  physiological  peculi- 
arities of  their  nutrition  and  reproduction,  are 
the  object  of  numerous  labors,  and  give  rise  to 
passionate  discussions  relating  to  the  subject  of 
spontaneous  generation,  polymorphism  of  fungi, 
theories  of  fermentation,  and  the  pathology  of 
virulent  and  infectious  maladies.  For  this  reason 
an  exposition  of  these  researches,  often  contradic- 
tory, is  extremely  difficult.  We  will  make  it  suc- 
cinctly, insisting  especially  upon  the  labors  relating 
to  the  classification  of  the  bacteria,  and  reserving 
to  ourselves  the  privilege  of  returning  to  the  his- 
tory of  several  points,  when  we  approach  their 
study  in  the  special  chapters  of  this  thesis. 

The  first  important  memoir  published  after 
that  of  M.  Davaine  upon  the  bacteria  is  that  of 
M.  Hoffmann,  in  1869.  He  demonstrates :  First, 
that  the  bacteria  are  plants,  having  a  very  distinct 
cellular  organization ;  second,  that  they  can  only 
be  classified  in  accordance  with  their  form  and 
size,  at  first  into  monads  and  linear  bacteria,  and 
the  latter  into  microbacteria,  mesobacteria,  and 
megabacteria ;  (M.  Hoffmann  includes  with  the 
linear  bacteria,  Vibrio,  Bacterium,  and  Leptotlirix, 
which  are  bacteria  united  in  a  chaplet ;)  third, 
that  mobility  or  immobility  is  not  a  specific  char- 
acter, but  may  present  itself  in  the  same  species 
under  the  influence  of  changes  of  temperature,  of 
density  of  medium,  etc.  M.  Hoffmann  studied 
also  the  origin  of  the  bacteria,  and  rejects  the 
hypothesis  of  a  spontaneous  generation.  As  to 


HISTORICAL.  21 

their  role  in  the  phenomena  of  the  decomposition 
of  organic  bodies  and  in  fermentations,  M.  Hoff- 
mann confesses  "  that,  with  the  exception  of  yeast 
and  of  the  acetic  and  butyric  ferments,  all  the  rest 
is  still  enveloped  in  obscurity." 

M.  Cohn  is  the  naturalist  who,  in  our  days,  has 
occupied  himself  the  most  with  the  bacteria.  In 
1853,  he  published  his  first  researches  upon  this 
subject.  The  genera  Zoogloea,  which  he  estab- 
lished at  this  time  for  the  bacteria  arranged  in  ge- 
latinous masses,  diffused  or  more  or  less  crowded 
together,  was  not  a  happy  creation.  It  was  adopt- 
ed at  first  by  M.  Rabenhorst  who,  in  his  work  on 
the  fresh-water  algae  of  Europe,  places  them  after 
the  palmellaceae,  while  he  classes  the  other  bac- 
teria, Vibrio  and  Spirillum,  in  the  family  of  the 
oscillatoriae.  The  Zooglcea  were  later  abandoned  by 
their  author  as  a  generic  group,  and  are  preserved 
only  as  the  name  of  one  of  the  diverse  transitory 
stages  through  which  the  bacteria  pass  in  .the 
course  of  their  evolution  (Zooglcea,  Leptothrix, 
Toruld). 

Twenty  years  later  the  same  savant  commenced 
the  publication  of  a  series  of  "  Memoirs "  upon 
these  organisms  (in  his  "  Beitrage  zur  Biologie  der 
Pflanzen").  In  the  first  paper  the  author  gives  an 
exposition  of  his  researches  upon  the  organization, 
development,  and  classification  of  the  bacteria,  and 
upon  their  action  as  ferments. 

M.  Cohn  considers  them  as  a  well-defined  group, 
—  the  schizospores,  belonging  to  the  algae,  at  the 
commencement  of  the  series  of  the  phycochroma- 


22  THE   BACTERIA. 

cese,  with  several  families  with  which  the  different 
genera  of  bacteria  have  many  affinities.  He  rec- 
ognized, however,  that  the  absence  of  chlorophyll 
approaches  them,  at  least  from  a  functional  point 
of  view,  to  the  fungi.  Upon  this  point  we  may 
say  that  for  other  botanists  this  character  is  de- 
cisive, and  the  bacteria  are  classed  as  fungi. 

M.  N'ageli,  who  takes  this  view,  describes  them 
under  the  name  of  Schizomycetes.  Cohn  divides 
the  bacteria  into  four  tribes,  comprising  six 
genera :  — 

1.  The  Sphcerobacteria  or  globular  B. 

2.  The  Microbacteria  or  rod  B. 

3.  The  Desmobacteria  or  filamentous  B. 

4.  The  Spirobacteria  or  Spiral  B. 

We  will  return  to  this  classification. 

In  1874,  M.  Th.  Billroth,  in  his  researches  upon 
the  Coccobacteria  septica,  expressed  opinions  en- 
tirely different  from  those  of  Cohn.  According 
to  Billroth,  the  bacteria  differ  considerably  in 
form  according  to  the  medium  in  which  they  are 
placed  and  divers  circumstances.  He  claims  that 
they  constitute  but  a  single  species,  the  C'occobac- 
teria  septica.  This  vegetable  organism  can  pre- 
sent itself  under  the  form  of  globular  articles 
(coccos)  or  under  that  of  rods  (bacterie).  These 
two  forms  may  reproduce  themselves  by  becoming 
elongated  and  dividing  transversely,  or  may  pass 
the  one  into  the  other.  Billroth  claims  to  have 
found  both  forms  united  in  a  single  filament,  a 


HISTORICAL.    .  23 

fact  which  in  his  opinion  demonstrates  conclu- 
sively their  relationship.  Each  of  these  two 
forms  can  also  present  variations  of  size,  in  ac- 
cordance with  which  he  establishes  the  following 
divisions :  — 

Micrococcos Microbacteria. 

Mesococcos Mesobacteria. 

Megacoccos Megabacteria. 

And  varieties  of  association  which  give  rise  to  the 
following  names :  — 

Monococcos Monobacteria. 

Diplococcos Diplobacteria. 

Streptococcos Strep  tobacteria. 

Gliacoccos Gliabacteria. 

Petalococcos Petalobacteria. 

Ascoccos. 

The  following  year  (1875),  Cohn,  in  the  second 
part  of  his  "  Researches  "  upon  the  bacteria,  criti- 
cised the  opinions  expressed  by  Billroth  in  the  pre- 
ceding memoir.  Cohn  believes  that  we  should 
regard  as  distinct  genera  and  species  all  the  bac- 
teria having  a  particular  form  and  acting  differ- 
ently as  ferments,  so  long  as  the  proof  of  their 
identity  has  not  been  demonstrated  in  an  evident 
manner.  Coming  back  also  to  the  affinities  and 
classification  of  these  organisms,  he  insists  anew 
upon  their  near  relationship  to  the  Phycochro- 
macese;  and,  no  longer  distinguishing  the  bac- 
teria as  a  special  family,  he  distributes  his 
different  genera  in  a  group,  which  he  calls  Schi- 
zopkytes,  which  includes  the  greater  part  of  the 


24  THE  BACTERIA. 

r 

Chrococcece  and  of  the  Oscillarice.  We  will  re- 
turn to  this  subject  when  we  speak  of  the  clas- 
sification of  the  bacteria. 

In  1876,  appeared  in  the  same  number  of 
Cohn's  "  Beitrage "  two  important  papers.  The 
first,  by  Cohn,  treats  of  the  influence  of  tempera- 
ture upon  the  bacteria,  of  •  their  origin,  of  the 
formation  of  spores  ;n  the  Bacillus  of.  hay  infu- 
sion, and  of  charbon.  The  second,  by  Koch, 
gives  the  result  of  his  researches  upon  the  bac- 
teria of  charbon,  the  Bacillus  anthracis. 

Koch  has  been  able  by  skilful  cultivation  to 
follow  the  complete  development  of  this  Bacillus, 
and  to  witness  the  formation  of  spores,  of  which 
the  vitality  is  very  great,  and  which  are  the  prin- 
cipal agents  of  the  transmission  of  this  terrible 
malady. 

I  must  still  indicate,  in  addition  to  these  special 
works,  a  quantity  of  notes  and  of  memoirs  scat- 
tered through  the  reviews  and  periodical  publica- 
tions. 

The  list  will  be  found  in  the  bibliography  ap- 
pended to  this  work.  I  must  also  cite  the  recent 
work  of  M.  Nageli  upon  "  The  Inferior  Fungi 
and  their  Role  in  Infectious  Maladies."  The 
learned  professor  of  Munich  has  studied  the  di- 
verse fungi  which  produce  decompositions.  He 
divides  them  into  three  groups,  —  the  Mucorini, 
the  Saccharomycetes,  and  the  8M0ompcetes,  which 
correspond  to  the  bacteria.  According  to  Niigeli, 


HISTORICAL.  25 

the   bacteria   are  fungi  which  produce  putrefac- 
tion. 

In  presence  of  these  opinions,  so  diverse,  as  to 
the  nature  of  the  bacteria  and  their  classification, 
we  will  finish  by  saying  with  Cohn :  — 

"  So  long  as  the  makers  of  microscopes  do  not 
place  at  our  disposal  much  higher  powers,  and,  as 
far  as  possible,  without  immersion,  we  will  find 
ourselves,  in  the  domain  of  the  bacteria,  in  the 
situation  of  a  traveller  who  wanders  in  an  un- 
known country  at  the  hour  of  twilight,  at  the 
moment  when  the  tight  of  day  no  longer  suffices 
to  enable  him  clearly  to  distinguish  objects,  and 
when  he  is  conscious  that,  notwithstanding  all  his 
precautions,  he  is  liable  to  lose  his  way." 


PART   FIRST. 
MORPHOLOGY   OF  THE   BACTERIA, 

CHAPTER  I. 

ORGANIZATION   OF  THE   BACTERIA. 

WHEN  bacteria  develop  in  a  liquid  in  a  suffi- 
cient quantity,  they  become  visible  to  the  naked 
eye.  They  appear  either  as  a  slight  cloud,  or 
gathered  in  little  masses  in  the  liquid,  or  forming 
a  pellicle  upon  its  surface,  or  as  a  deposit  upon  the 
walls  of  the  vessel  and  upon  the  objects  contained 
in  the  liquid.  However,  we  must  hasten  to  say 
with  M.  Cohn,  that  the  fact  of  the  absence  of  all 
turbidity  in  a  liquid  does  not  exclude  the  possi- 
bility of  the  presence  of  bacteria.  In  liquids  more 
dense  than  water  (serum,  lymph,  etc.),  when  the 
refractive  power  of  these  corpuscles  is  the  same  as 
that  of  the  liquid,  their  presence  may  not  be 
revealed  to  the  naked  eye.  We  will  add  that 
sometimes  their  color  serves  to  indicate  their 
presence  in  a  liquid,  although  this  color  is  often 
very  feeble,  and  can  only  be  perceived  when  a 
considerable  thickness  of  the  liquid  is  examined. 
If  we  examine  these  clouds,  these  accumulations, 
these  deposits,  with  the  microscope,  we  see  that 


28       MORPHOLOGY  OF  THE  BACTERIA. 

they  are  formed  of  a  myriad  of  little  bodies  'iso- 
lated or  grouped,  globular  or  linear,  gifted  or  not 
with  motion,  sometimes  colored.  These  variations 
constitute  so  many  characters  which  require  to  be 
studied  with  some  detail. 


§  1.  BACTERIA  IN  GENERAL. 

Form.  —  The  bacteria,  as  understood  to-day  by 
most  botanists,  when  considered  in  their  separate 
state,  are  of  two  principal  forms,  —  globular  bod- 
ies, or  monads,  and  bodies  more  or  less  filiform,  or 
bacteria  properly  so  called. 

The  globular  bacteria  comprise  organisms  round- 
ed, ovoid,  sometimes  elongating  themselves  into  a 
tube  (Warming).  The  Monas  crepusculum  of 
Ehrenberg  may  be  taken  as  a  type.  This  form 
includes  also  the  Micrococcus  of  Hallier,  the  Mi- 
crosporon  of  Klebs,  the  round  forms  of  the  Amy- 
lobacter  of  M.  Trecul,  and  perhaps  the  Microzyma 
of  M.  Bechamp.  We  will  see  farther  on  that 
these  are  very  probably  phases  of  development  of 
the  spores  of  bacteria,  properly  so  called. 

The  bacteria,  not  globular,  present  a  greater 
diversity  of  form  ;  they  may  be  straight,  undu- 
lating, or  twisted  in  a  spiral. 

The  rectilinear  bacteria  are  usually  exactly 
cylindrical  throughout  their  whole  extent ;  and  in 
this  case  they  form  very  short  cylinders,  as  in  the 
Bacterium,Cohn,  or  cylinders  of  which  the  length 
is  several  times  as  great  as  the  thickness,  as  in 
the  Bacteridies  (Bacillus  ulna  Cohn) ;  others  are 


ORGANIZATION  OF  THE  BACTERIA.  29 

swollen  in  the  middle,  with  their  extremities 
rounded,  such  as  certain  forms  of  Vibrio  serpens 
(Warming) ;  others  again  are  fusiform,  swollen  in 
the  middle  and  attenuated  at  the  extremities, — 
Bacterium  fusiforme  (Warming) ;  rectilinear  bac- 
teria swollen  at  the  two  extremities  are  met 
during  the  life  of  certain  species,  B.  lineola  and 
B.  termo,  for  example,  above  all  when  they  are 
transported  to  a  more  favorable  medium :  this 
modification  usually  precedes  segmentation  ;  final- 
ly, one  meets  sometimes  bacteria  swollen  at  one 
extremity  only;  the  swollen  part  presents  often 
a  clear  point  and  sometimes  an  evident  spore  :  we 
shall  see  later  the  signification  of  this  peculiarity. 
With  these  claviform  bacteria  we  may  include  the 
Bacterium  capitalum  Dav.,  the  Helobacteria  of 
Billroth,  and  certain  Amylobacter,  with  heads  of 
the  Ficus  carica,  etc.  (Ch.  Robin). 

The  undulating  bacteria  constitute  the  Vibrios 
properly  so  called  (V.  rugula,  serpens,  etc.). 

The  spiral  bacteria  of  which  the  turns  are  more 
or  less  elongated  are  named  Spirillum,  Spiro- 
chceta,  etc. 

Dimensions.  —  The  dimensions  of  the  bacteria 
oscillate  between  the  most  variable  limits,  but  in 
a  general  way  it  may  be  said  that  they  are  the 
smallest  of  all  microscopic  beings.  Some  of  them 
are  situated  at  the  extreme  limit  of  our  highest 
magnifying  powers;  and  their  proportions,  as  to 


30       MORPHOLOGY  OF  THE  BACTERIA. 

length  and  thickness,  are  comprised  within  the 
limits  of  errors  of  observation. 

The  globular  bacteria  are  the  smallest,  and  the 
dimensions  of  some  species  are  so  minute  that 
they  cannot  be  measured  directly. 

The  largest  are  the  Spirillum,  which  attain  a 
length  of  y2^-  of  a  millimetre.  Between  these  two 
extremes,  there  are  all  intermediary  sizes  possible. 
The  dimensions  of  some  of  the  bacteria  are  given 
below:  — 

Monas  vinosa,  0.5  to  1  /-t,  in  diameter;  length  3 
to4|k 

Bacterium  termo,  breadth  0.6  to  0.8  ^;  length  2 
to  3/4. 

Vibrio  lineola,  breadth  0.5  to  1  p ;  length  3  to  8  //,. 

Bacillus  ulna,         „     0.7  to  1  /z ;       „      5  to  8  /it. 

B.  anthracis,  „     1     to  2  //, ;       ,,10  to  50  p. 

Spirillumvolutans,  „  7  /z ;       ,,10  to  40  JJL. 

Several  authors,  considering  exclusively  this 
character  of  dimensions,  have  divided  the  monera 
and  the  bacteria  according  to  their  size.  Thus 
Hoffmann  recognizes  in  addition  to  the  monera, 
only  the  microbacteria,  the  mesobacteria,  and  the 
macrobacteria.  In  the  same  way  Billroth  classi- 
fies the  monads  according  to  their  dimensions  into 
micro,  meso,  mega  coccos,  and  the  bacteria  into 
micro,  meso,  mega  bacteria.  Finally,  Klebs  sep- 
arates the  Micrococcos  from  the  Microsporines, 
which  do  not  differ  from  them  except  by  their 
smaller  dimensions,  both  forms  being  able  to  pass 
to  the  state  of  bacteria  (rods). 


ORGANIZATION  OF  THE  BACTERIA.  31 

Color.  —  The  phenomena  relating  to  the  color 
of  bacteria  have  only  recently  been  pointed  out. 
"  But  little  attention  has  been  given  to  the  color 
of  the  bacteria,  regarded  generally  as  colorless," 
said  M.  de  Seynes  in  1874 ;  and  recently  M.  de 
Lanessan,  "  The  bacteria  are  ordinarily  quite  color- 
less." However,  M.  Cohn  had  already  insisted 
upon  the  globular  bacteria  chromogenes,  or  of  pig- 
mentary fermentation,  and  upon  the  colors  pro- 
duced by  different  monads,  which  have  long  since 
been  studied  by  microscopists. 

Upon  this  subject,  let  us  observe  that  the  bac- 
teria which  are  colored  belong  to  two  very  dif- 
ferent groups.  First,  colored  organisms  always 
known  as  such,  but  which  were  not  formerly  in- 
cluded with  the  bacteria,  as  the  different  monads, 
which  have  become  the  Micrococcus  prodigiosus, 
cyaneus,  aurantiacus,Cohn,  etc. ;  the  second  group 
includes  the  bacteria  properly  so  called,  which 
absorb  the  coloring  matter  of  vegetables  upon 
which  they  are  fixed  as  parasites,  or  of  the  media 
in  which  they  live.  This  is  the  case  with  the  bac- 
teria observed  by  M.  de  Seynes  upon  the  Penicil- 
lium  glaucum,  and  perhaps  with  the  Vibrio  syn- 
xanthus  and  sy?icyam^s,Ehrenb.,  which  give  to  milk 
a  yellow  or  blue  color  according  to  the  species. 
We  will  return  to  this  subject  when  we  speak  of 
the  nutrition  of  the  bacteria. 

As  to  the  purple-colored  monads,  they  have 
been  especially  studied  as  early  as  1838  by  Dunal, 
then  by  Morren  and  Ehrenberg,  and  in  our  own 
day  by  Kay-Lankester,  Cohn,  Klein,  and  finally 


32        MORPHOLOGY  OF  THE  BACTERIA. 

by  Warming  and  Giard.  They  are  found  in  va- 
rious media  —  in  sea- water,  in  hot  sulphur  springs, 
in  fresh  water  containing  animal  or  vegetable  mat- 
ter in  a  state  of  putrefaction.  They  appear  some- 
times upon  bread,  meats,  and  in  general  upon 
cooked  food  placed  in  a  humid  atmosphere.  The 
different  colors  which  they  present  are  red,  yel- 
low, orange,  and  blue.  It  is  probably  to  anal- 
ogous organisms  that  we  must  attribute  the  blue 
color  presented  by  pus  under  certain  circum- 
stances, the  green  and  blue  color  studied  by 
M.  Chalvet,  and  the  orange-yellow,  bright  red, 
and  blue  colors  observed  by  C.  Eberth  in  perspi- 
ration. 

In  Norway,  red  bacteria  appear  in  summer  in 
such  masses  that  the  borders  of  the  sea  are  some- 
times colored  of  an  intense  red  (Warming). 

Movement.  —  The  bacteria  are  met  in  two  dif- 
ferent states.  They  are  active  or  motionless ;  but 
it  is  now  well  settled  for  the  greater  number  that 
the  same  species  may  present  itself  sometimes  in 
a  state  of  repose,  sometimes  in  a  state  of  move- 
ment. 

The  movements  of  the  bacteria  are  of  two  kinds, 
—  a  movement  of  the  corpuscle  upon  itself  and  a 
movement  of  translation.  The  first  is  sometimes 
nothing  more  than  a  molecular  or  brownien  move- 
ment, which  occurs  in  the  smallest  forms.  But  at 
other  times  it  is  more  extended,  and  consists  in  a 
movement  of  rotation  round  the  axis,  or  a  bend- 
ing of  the  body.  This  flexibility  is,  above  all, 


ORGANIZATION  OF  THE  BACTERIA.  33 

observed  in  the  long  forms,  the  Bacillus,  the  V'ib- 
rions,  etc.  As  to  the  movement  of  translation, 
it  is  very  variable ;  at  one  time  slow,  at  another 
rapid,  it  is  in  relation  with  the  length  and  form 
of  the  bacterium.  M.  Cohn  has  well  described  all 
the  modifications  of  movement  in  the  following 
lines :  — 

"  Almost  all  the  bacteria  possess  two  different 
modes  of  life,  characterized  by  repose  and  by 
movement. 

"  In  certain  conditions,  they  are  excessively 
mobile ;  and  when  they  swarm  in  a  drop  of 
water,  they  present  an  attractive  spectacle,  sim- 
ilar to  that  of  a  swarm  of  gnats,  or  an  ant-hill. 
The  bacteria  advance,  swimming,  then  retreat 
without  turning  about,  or  even  describe  circular 
lines.  At  one  time  they  advance  with  the  ra- 
pidity of  an  arrow,  at  another,  they  turn  upon 
themselves  like  a  top ;  sometimes  they  remain 
motionless  for  a  long  time,  and  then  dart  off 
like  a  flash.  The  long  rod-bacteria  twist  their 
bodies  in  swimming,  sometimes  slowly,  sometimes 
with  address  and  agility,  as  if  they  tried  to  force 
for  themselves  a  passage  through  obstacles.  It 
is  thus  that  the  fish  seeks  its  way  through  aquatic 
plants.  They  remain  sometimes  quiet,  as  if  to  re- 
pose an  instant:  suddenly  the  little  rod  commences 
to  oscillate,  and  then  to  swim  briskly  backwards, 
to  again  throw  itself  forward  some  instants  after. 
All  of  these  movements  are  accompanied  by  a 
second  movement  analogous  to  that  of  a  screw 
which  moves  in  a  nut.  When  the  vibrios"  in  the 

3 


34  MORPHOLOGY  OF  THE  BACTERIA. 

shape  of  a  gimlet  turn  rapidly  round  their  axis, 
they  produce  a  singular  illusion :  one  would  be- 
lieve that  they  twisted  like  an  eel,  although  they 
are  extremely  rigid." 

The  causes  of  these  movements  have  been  sought, 
at  first,  in  the  supposed  animal  nature  of  the  bac- 
teria, and  the  movements  assimilated,  consequently, 
to  voluntary  movements  ;  but  this  opinion  can  no 
longer  be  sustained,  as  similar  movements  are  to 
be  seen  in  a  great  number  of  vegetable  organisms, 
such  as  the  diatoms,  the  oscillatorise,  the  spores  of 
algae  and  some  fungi,  etc.  They  have  also  been 
attributed  to  the  existence  of  locomotor  appen- 
dices (Ehrenberg) ;  but,  although  the  cilia,  denied 
at  first  by  most  microscopists,  have  been  seen  since 
in  nearly  all  the  bacteria,  the  botanists  who  have 
best  studied  them,  M.  Warming,  for  example,  rec- 
ognize that  it  is  scarcely  probable  that  these  or- 
gans are  the  cause  of  their  movements,  for  "  one 
meets  some  examples  in  which  the  body  remains 
motionless  while  the  cilia  are  in  violent  agitation, 
and  others  in  which  the  body  moves  while  the  cilia 
remain  inert,  or  dragging  behind." 

The  movements  appear  to  depend  rather  upon 
the  nutrition,  or  respiration,  and  especially  upon 
the  presence  of  oxygen  (Cohn);  indeed  when  this 
gas  is  wanting  the  bacteria  become  motionless. 
Immobility  may  also  be  produced  by  want  of 
nutriment,  poisoning  by  different  toxic  substances, 
(chloroform,  iodine,  etc.),  dessication,  etc. 

The  attempt  has  been  made  to  use  the  charac- 
ters derived  from  the  existence  or  absence  of 


ORGANIZATION  OF   THE  BACTERIA.  35 

motion,  and  the  form  of  the  bacteria,  in  order  to 
classify  them ;  but  what  has  just  been  said  shows 
clearly  that  these  transitory  phenomena  cannot  be 
taken  for  generic  or  specific  characters. 

Structure.  —  It  was  for  a  long  time  believed  that 
the  bacteria  were  constituted  of  amorphous  masses 
of  protoplasm,  or  of  solid  rods.  The  researches  of 
Hoffmann  have  shown  that  they  have  a  true  cellu- 
lar structure.  We  shall  describe,  then,  succes- 
sively, their  membrane,  the  contents,  and  the  cilia, 
which  may  be  considered  as  belonging  to  the  pro- 
toplasm. 

Cell-membrane. — The  extreme  minuteness  of 
the  bacteria  usually  prevents  a  direct  demonstra- 
tion of  the  cell-membrane,  and  the  existence  of 
this  envelope  has  not,  heretofore,  been  clearly 
demonstrated  except  by  indirect  proofs ;  chemical 
reactions,  for  example. 

Thus  Hoffmann  verifies  the  existence  of  a  cellu- 
lar envelope  when  "  the  contents,  which  is  a  trans- 
parent plasma,  are  partly  coagulated,  as  sometimes 
happens,  or  disappear,  and  are  then  replaced  by 
air  which  shows  precisely  the  form  of  the  normal 
bacterian  cell."  Warming,  also,  has  not  been  able 
to  see  the  membrane,  "  which  only  appears  dis- 
tinctly when  a  vacuole  has  formed  just  against  the 
periphery." 

On  the  other  hand,  the  action  of  chemical  agents 
upon  bacteria  proves  that  they  have  an  envelope 
of  cellulose,  which  is  colored  by  tincture  of  iodine ; 


36  MORPHOLOGY  OF  THE  BACTERIA. 

is  not  destroyed  by  caustic  potash,  ammonia,  or 
even  acids;  and  resists  putrefaction  for  an  ex- 
ceedingly long  time.  In  this  respect,  it  resem- 
bles the  membrane  of  cellulose  of  vegetable  cells 
(Cohn). 

We  should  add  that  Cohn  claims  to  have  suc- 
ceeded with  high  powers  in  seeing  directly  the 
cell-membrane.  On  the  other  hand,  ^Yarming  has 
never  succeeded  in  so  doing.  The  last  observer 
remarks  also  that  the  resistance  of  bacteria  to 
acids,  to  alkalis,  etc.,  does  not  seem  to  prove  the 
existence  of  a  membrane,  "  inasmuch  as  this  may 
be  the  result  of  a  particular  condition  of  the 
plasma,  which  in  all  the  bacteria  is  of  a  more  con- 
sistent nature  than  in  other  plants." 

Finally,  the  membrane  may  be,  in  certain  bac- 
teria, tender,  flexible  and  susceptible  of  move- 
ments of  torsion.  In  others,  it  is  rigid  and 
incapable  of  bending.  Cohn  thinks  also  that  it 
may  swell  and  dissolve  into  mucilage,  a  fact  which 
would  explain  the  origin  of  this  substance  in  the 
Zooglcea. 

Protoplasm.  —  The  contents  of  the  cell  is  a 
nitrogenous  substance,  generally  colorless,  more 
highly  refractive  than  water. 

In  the  smallest  species,  this  protoplasm  appears 
homogeneous ;  but  in  the  bacteria  of  medium  size, 
and  above  all  in  the  large  species,  the  contents  of 
the  cell  encloses  portions  more  highly  refractive, 
vacuoles,  special  granules,  and  sometimes  diverse 
coloring  matters. 


ORGANIZATION  OF  THE  BACTERIA.  37 

Cohn  first  pointed  out  the  movements  of  the 
protoplasm,  in  which  currents  occur,  above  all  in 
the  central  portion,  the  peripheral  portion  remain- 
ing homogeneous  and  motionless.  The  vacuoles 
are  also  found  in  the  central  portion ;  Warming, 
however,  who  has  observed  them  in  Monas  Okenii, 
Vibrio  rftgula,  V.  serpens  and  Spirillum  undula 
var.  littoreum,  has  sometimes  seen  them  in  the  mid- 
dle of  the  plasma,  at  another  near  the  exterior  wall. 

The  granules  which  are  seen  in  the  protoplasm 
were  considered  by  Ehrenberg  as  stomachal  vesi- 
cles or  ovules.  They  are  of  two  sorts  ;  the  one, 
highly  refractive  and  not  bordered  by  a  dark  circle, 
are  considered  by  Warming  as  nothing  more  than 
mere  compact  masses  of  protoplasm ;  the  second, 
also  highly  refractive,  but  surrounded  by  a  dark 
circle,  resemble  drops  of  oil,  and  have  been  taken 
for  fat  granules ;  but  the  recent  researches  of 
Cramer,  Cohn,  and  Warming  have  proved  that 
some  of  them,  at  least,  are  formed  of  crystalline 
sulphur.  They  are  not  soluble  either  in  hydro- 
chloric acid  or  in  water,  but  they  are  dissolved  in 
absolute  alcohol,  in  hot  caustic  potash  and  sulphite 
of  soda,  in  nitric  acid  and  chlorate  of  potash  at 
ordinary  temperatures,  and  in  bisulphide  of  carbon, 
when  the  membrane,  which  is  permeable  with  dif- 
ficulty, has  been  previously  destroyed  by  sulphuric 
acid.  Although  their  small  dimensions  and  great 
refractive  power  prevent  them  from  being  dis- 
tinguished with  certainty  as  crystals  of  sulphur,  as 
they  are  doubly  refractive  to  polarized  light  their 
crystalline  nature  cannot  be  doubted. 


38       MORPHOLOGY  OF  THE  BACTERIA. 

These  globules  of  sulphur  have  been  observed 
in  Monas  Okenii,  Bacterium  sulphuratum,  Ophi- 
domonas,  and  the  different  species  of  Beggiatoa, 
both  in  fresh  water,  in  putrid  sea- water,  and  in 
thermal  sulphur  waters.  It  will  be  seen  when  we 
speak  of  the  physiology  of  these  organisms  what 
their  role  is  in  the  elimination  of  sulphui*  and  the 
formation  of  sulphuretted  hydrogen. 

We  have  said,  in  speaking  of  the  colored  bac- 
teria, that  some  borrow  their  color  from  the  sur- 
rounding medium,  and  that  others,  on  the  contrary, 
have  a  color  of  their  own.  The  protoplasm  of  the 
latter  contains  a  granular  coloring  matter,  which 
is  ordinarily  yellow,  blue,  or  red.  The  red  color- 
ing matter  is  most  common,  and  this  has  been  best 
studied,  and  appears  to  be  the  best  known. 

One  of  these  colors  which  gives  a  pink  tint 
(peach  color)  to  Bacterium  rubescens,  Ray-Lank. 
( Clathrocystis  roseopersicina,  Cohn);  Monas  tnnosa, 
Ehrb.,  M.  OJcenii,  Cohn ;  M.  gracilis,  Warming ; 
Rhabdomonas  rosea,  Cohn;  M.  Warmingii,  Cohn; 
Ophldomonas  sanguinea,  Ehrb. ;  Merismopedia 
littoralis,  Rabenh. ;  etc.,  has  been  studied  by  Ray- 
Lankaster,  who  has  given  to  it  the  name  of  bac- 
terio-purpurine.  It  is  insoluble  in  water,  soluble 
in  alcohol,  ether,  carbolic  acid,  glycerine,  and 
fatty  oils, —  characteristics  which  make  it  resemble 
chlorophyll.  It  has  also  a  characteristic  spectrum. 

Other  red  coloring  matters  which  appear  to  be 
different  have  been  found  in  Monas  prodigiosa9 
Ehrb.;  Bacillus  ruber,  Cohn;  and  Micrococcus ful- 
vus,  Cohn.  These  should  not  be  confounded  with 


ORGANIZATION  OF  THE  BACTERIA.  39 

the  purple  coloring  matter  of  other  algae,  as  that 
of  the  Porphyridium  cruentum,  which  comes  from 
a  mixture  of  chlorophyll  and  of  phycoerythrine. 
The  bacteria  never  contain  chlorophyll. 

In  this  connection,  it  is  interesting  to  recall  the 
protoplasmic  constitution  of  the  Amylobacter  of 
Trecul.  These  organisms  are,  according  to  Yan 
Tieghern,  bacteria,  to  which  he  has  given  the  name 
of  Bacillus  Amylobacter,  and  which  does  not  dif- 
fer from  B.  subtilis,  except  by  a  specific  character, 
extremely  transitory,  —  the  presence  of  amorphous 
starch,  formed  and  stored  in  reserve  during  the 
period  of  growth,  to  be  again  used  later,  and  con- 
sumed during  the  process  of  reproduction. 

Cilia. — These  appendages  which  were  described 
by  Ehrenberg  in  the  Bacterium  trilocular  have 
not  been  seen  since.  To-day,  recent  researches 
permit  us  to  say  that  cilia  exist  without  doubt  in 
all  the  true  bacteria,  —  Bacillus,  Bacterium,  Spi- 
rillum. They  have  been  perceived  in  a  great 
number  of  forms, — Spirillum  volutans,  Sp.  undula, 
Vibrio  rugula,  Spiromonas  Cohnii,  Vibrio  ser- 
pens,  and  several  species  of  Bacillus.  It  is  only 
in  the  smallest  of  the  bacteria  that  it  has  hitherto 
been  impossible  to  demonstrate  their  presence. 
They  have,  however,  been  recently  seen  by  Dai- 
linger  and  Drysdale  in  Bacterium  termo.  Warm- 
ing has  perceived  as  many  as  two  or  three  on  one 
extremity  in  Ophidomonas  sanguinea  Spirillum 
volutans  var.  robuslum,  arid  Vibrio  rugula. 


PLATE  I. 

Taken  from  "  Monthly  Microscopical  Journal,"  of  Sept.  1st,  1875. 

FIG  1.  — a.  B.  termo  magnified  with  the  same  power  as  b,  which 
is  a  specimen  of  Spirillum  volutans,  showing  flagella  at  each  end. 

FIG.  2.  —  B.  termo,  as  seen  with  a  power  of  about  600  diameters. 

FIG.  3.  —  The  same  as  seen  with  -^  and  second  eye-piece  (3,700 
diameters). 

FIG.  4.  — B.  termo,  seen  with  flagellum  at  one  end,  the  light  com- 
ing in  the  direction  of  the  arrow. 

FIG.  5.  —  The  same  object  when  it  moved  at  right  angles  to  its 
former  position,  the  light  coming  from  the  same  direction,  causing 
the  sight  of  the  flagellum  to  be  lost. 

FIG.  6  represents  one  B.  termo  which  was  in  a  still  condition, 
but  one  flagellum  moving.  The  light  came  in  the  direction  of  the 
arrow.  When  the  end  marked  2  b  was  in  focus,  a  flagellum  was 
seen,  but  none  at  the  end  c.  When  the  end  marked  1  a  was  fo- 
cused carefully,  the  flagellum  at  that  end  was  seen,  and  lost  at  the 
end  d. 

FIG.  7.  —  The  true  form  of  B.  termo. 

FIG.  8.  —  The  form  as  shown  by  the  "  supplementary  stage  "  il- 
lumination before  flagella  were  found,  showing  the  pointed  ter- 
mination of  the  body  at  a,  b. 


PLATE  1 . 


4'2       MORPHOLOGY  OF  THE  BACTERIA. 

were  resolved  into  beads  with  the  third  and  fourth  eye-pieces.  In  like 
manner  the  fine  striae  in  Surirella  gemma  were  instantly  shown  to  be 
beaded,  with  perfect  and  brilliant  definition,  with  the  second  eye-piece. 
Nacicula  rhomboides  and  an  extremely  delicate  specimen  of  Pleurosigma 
attenuatum  which  had  resisted  everything  below  a  ^th  immersion,  showed 
beaded  striae  perfectly.  We  were  therefore  encouraged  to  try  again  to 
discover  flagella  in  the  termo.  Some  of  our  specimens,  nourished  in 
Cohn's  nutritive  fluid,  were  placed  in  a  drop  of  distilled  water,  and  put 
upon  the  supplementary  stage  on  an  ordinary  slide  covered  with  the 
thinnest  cover.  The  utmost  delicacy  and  tact  in  manipulation  of  the 
light  is  the  great  desideratum ;  but,  with  this,  enough  may  be  secured  to 
work  with  the  fourth  eye-piece.  The  light  may  be  made  to  enter  the 
objective  at  almost  every  angle,  but  it  is  always  projected  in  a  direction 
at  right  angles  to  the  stage ;  and  the  first  thing  we  observed  when  the 
objects  were  sufficiently  slow  in  their  movements,  and  at  right  angles  to 
the  light,  was  that  the  ends  of  the  termo,  which  we  (and  all  other  observers, 
as  far  as  we  know)  had  taken  for  round,  proved  themselves  to  be  conical, 
terminating  in  a  sharp  point.  The  usual  appearance  of  B.  termo,  as  seen 
with  a  magnification  of  about  600  diameters,  is  seen  in  Fig.  2  ;  whilst  the 
same  seen  with  a  magnifying  power  of  3,700  diameters  (sVth  and  second 
eye-piece)  is  seen  in  Fig.  3,  where  a  globular  granule  is  seen  in  the  end 
of  each  half.  But  with  the  method  above  referred  to,  the  best  condi- 
tions being  secured,  the  two  ends  of  the  bacterium  were  distinctly  pointed, 
as  seen  at  a  b,  Fig.  8,  and  after  nearly  five  hours  of  incessant  endeavor 
a  flagellum  was  distinctly  seen  at  one  end  of  each  of  two  termos  which 
were  moving  slowly  across  the  field.  The  discovery  was  not  sudden  and 
transient,  but  lasted  for  at  least  twenty  minutes.  The  exquisitely  delicate 
flagellum  was  lashing  rapidly  the  whole  time ;  and  one  of  its  frequent 
conditions  is  shown  in  Fig.  4,  the  arrow  indicating  the  direction  of  the 
light :  but  if  the  termo  turned  round  at  right  angles,  as  in  Fig.  5,  all  trace 
of  the  flagellum  was  gone,  showing  that  its  discovery  depended  entirely, 
all  things  being  equal,  upon  its  position  in  regard  to  the  light. 

"  But  this  observation  was  made  only  by  one  of  us,  the  other  not  being 
present ;  and  in  pursuance  of  our  plan  we  determined  to  see  it  again, 
convincing  ourselves  separately,  and  then  together.  After  many  hours 
of  labor,  this  wag  accomplished  ;  and  Fig.  6  shows  one  of  two  instances 
which  we  both  saw  together  at  the  same  time  and  in  the  same  instru- 
ment. It  was  lying  still,  obliquely  across  the  field,  the  light  coming  in 
the  direction  of  the  arrow.  Both  ends  were  not  perfectly  in  focus  at  the 
same  time,  but  in  focusing  the  end  marked  2  b  (Fig.  6)  the  flagellum 
was  distinctly  seen,  and  was  seen  also  to  coil  and  lash  ;  but  no  flagellum 
was  then  seen  at  the  end  c  of  the  same  object ;  but  by  bringing  it  into 
delicate  focus  it  presented  the  aspect  seen  at  1  a  (Fig.  0),  which  really 
represents  the  same  object  at  the  same  time,  only  with  the  other  end  in 
the  focus,  while  the  end  marked  d  corresponding  to  2  b  of  Fig.  6  was  in 
its  turn  slightly  out  of  focus,  and  the  flagellum  lost  to  view.  This  ob- 
servation, made  together,  was  as  satisfactory  as  could  be  desired ;  and  it 


ORGANIZATION  OF  THE  BACTERIA.  43 

was  thus  demonstrated  that  there  was  a  flagellum  at  both  ends  of  the  or- 
dinary B.  termo. 

"  It  will  of  course  be  understood  that  it  is  by  no  means  an  easy  matter 
to  secure  the  demonstration ;  and  whenever  we  repeat  it,  it  must  always 
be  with  nearly  the  same  amount  of  trouble  and  patience,  although  we 
can  now  with  the  ordinary  condenser  detect  the  vortical  action,  both  in 
front  and  (occasionally)  behind  the  termo,  as  we  never  did  before.  But 
the  demonstration  of  the  ultimate  structure  of  a  fixed  object  —  as  for 
instance  Amphi pleura  pellucida  —  must  be  looked  upon  as  a  matter  of 
great  ease  in  comparison ;  and  that  for  many  reasons,  the  foremost 
being  the  motion  and  the  minuteness  of  the  object,  the  swift  play  of  the 
flagella,  their  similarity  in  optical  properties  to  the  fluid  in  which  bacte- 
ria live,  the  difficulty  of  retaining  them  in  focus,  and  of  getting  them  in 
such  a  position  in  relation  to  the  light  as  to  make  demonstration  possible. 
Of  course,  all  this  would  be  removed  if  dead  bacteria  would  answer,  but 
they  very  rarely  (indeed  only  once)  have  done  so  with  us.  The  flagel- 
lum needs  to  be  in  slow  motion  to  properly  show  itself ;  for  even  with 
the  more  delicate  and  minute  monads  it  is  a  difficult  thing  to  show  the 
flagella  in  dead  forms,  since  in  the  majority  of  cases  they  appear  to  be 
attracted  round  the  body  of  the  creature." 


§  2.  —  OF  THE  DIFFERENT  MODES  OF  GROUPING 
OF  THE  BACTERIA. 

The  bacteria  are  fouDd  in  different  media  in 
two  states,  —  free,  isolated  (unicellular  bacteria), 
or  united  several  together,  either  in  chains,  in 
filaments,  or  in  masses  of  greater  or  less  extent, 
and  sometimes  by  the  aid  of  a  mucous  substance 
in  which  they  are  imbedded. 

The  free  unicellular  bacteria  are  found  in  the 
Spirillum,  Bacillus,  Monas,  etc.  When  they  are 
united,  they  are  grouped  in  the  following 
modes :  — 

1.  Form  of  a  little  chain:  Torula,  Leptothrix. 
—  The  usual  method  of  multiplication  among  the 
bacteria  is  by  fission  ("  scissiparite") ;  each  cor- 
puscle divides  transversely,  and  gives  birth  to  two 


44  MORPHOLOGY  OF  THE  BACTERIA. 

new  individuals,  which  sometimes  become  sepa- 
rated completely  the  one  from  the  other,  to  form 
unicellular  bacteria,  sometimes  remain  united;  and 
segmentation  again  occurring  in  each  portion,  a 
chain  is  formed  of  articles  more  or  less  numerous. 

When  these  chains  are  formed  of  spherical  bac- 
teria, they  have  been  called  torulce ;  if  they  are 
formed  of  filiform  bacteria,  they  correspond  to 
leptothrix  (Robin).  The  morphological  difference 
between  the  torula  and  the  leptothrix  consists  in 
the  fact  that  in  the  first  the  articles  are  separated 
by  constrictions,  while  this  is  not  the  case  in  the 
second.  It  is  also  to  be  remarked,  according  to 
Cohn,  that  the  microbacteria  never  take  either 
of  these  forms.  Warming  states,  however,  that 
he  has  met  the  torula  form  in  Bacterium  lineola, 
B.  catenula,  and  B.  termo  (?). 

Billroth  has  called  these  two  forms  of  bacteria 
streptococcos  and  streptobacteria.  He  has  even 
considered  it  necessary  to  create  the  words  diplo- 
coccos  and  diplobacteria  for  organisms  constituted 
only  of  two  articles. 

Z.^Foj^m  of  Zooglcea.  —  Generally,  when  bacte- 
ria are  rapidly  multiplying,  they  remain  grouped 
in  masses,  swarms,  or  Zooylcea.  In  the  latter  con- 
dition, they  are  closely  pressed  against  each  other 
in  the  midst  of  a  viscous  substance,  hyaline,  ho- 
mogeneous, colorless,  and  constituting  masses 
more  or  less  diffused  or  definite,  in  irregular 
globes,  bunches,  or  tubes,  swimming  in  the  water 
or  near  its  surface.  When  the  bacteria  multiply 
abundantly,  the  cells  become  removed  from  each 


ORGANIZATION  OF  THE  BACTERIA.  45 

other,  so  as  to  leave  between  them  greater  inter- 
vals. The  masses  sometimes  attain  a  diameter  of 
several  centimetres. 

The  gelatinous  substance  in  which  the  bacteria 
are  included  seems  to  be  produced  by  a  thicken- 
ing and  jellification  of  this  cell-membrane,  or  by  a 
secretion  from  their  protoplasm,  but  the  latter 
view  seems  more  plausible  than  the  former  (De 
Lanessan). 

It  is  commonly  the  spherical  bacteria  (Micro- 
coccus)  and  the  microbacteria  (Bacterium)  which 
are  found  in  this  state. 

The  filiform  bacteria  and  the  spirilla  are  never 
found  in  gelatinous  masses  (Cohn).  Kay-Lankes- 
ter,  however,  claims  to  have  met  the  Spirillum 
tenue,  in  the  form  of  zoogloea,  and  Klein  the  Spi- 
rillum undula  and  rosaceum  (Warming). 

The  form  of  Zoogloea ,  properly  so  called,  gelat- 
inous and  thick,  has  never  been  found  by  Warm- 
ing in  infusions  of  sea-water. 

According  to  the  terminology  of  Billroth  the 
zooglcea  are  called  gliacoccos  and  glidbacteria 
(from  yXi'a,  mucus  substance). 

3.  Form  of  My  coder  ma.  —  In  certain  cases,  the 
bacteria  unite  on  the  surface  of  the  water,  or  of 
the  liquid  in  which  they  are  developed,  to  form  a 
thick  layer,  a  sort  of  membrane.  This  production 
called  mycoderma  by  Pasteur  is  a  sort  of  zooglcea, 
but  differs  from  it  by  the  absence  of  the  interme- 
diary mucous  substance.  The  bacteria  are,  how- 
ever, motionless,  although  living,  since  they  come 
to  the  surface  to  be  in  contact  with  oxygen,  which 
is  necessary  to  them. 


46  MORPHOLOGY  OF  THE  BACTERIA. 

The  petalococcos  and  petalobacteria  of  Billroth 
correspond  with  the  mycoderma  of  Pasteur. 

4.  Swarms. — We  have  seen  that  the  filiform 
and  spiral  bacteria  do  not,  usually,  form  zooglcea. 
These  microphytes  are  either  disseminated  and  free, 
or  united  in  swarms.  This  formation  may  be  seen, 
for  that  matter,  in  all  the  bacteria,  when,  thanks 
to  abundant  nourishment,  they  multiply  rapidly 
and  gather  together  in  considerable  masses.  They 
are  very  active  in  these  swarms,  whilst  in  the 
zooglcea  the  corpuscles  are  motionless,  because  of 
the  intermediary  glairy  substance. 

Pulverulent  precipitate.  —  When  the  nutritive 
elements  are  exhausted  in  a  liquid,  the  bacteria 
cease  to  multiply,  fall  to  the  bottom  of  the  recep- 
tacle, and  the  liquid  gradually  becomes  clear.  The 
deposit  formed  in  this  manner  may  acquire  a  thick- 
ness very  appreciable  to  the  naked  eye.  The  bac- 
teria which  form  this  precipitate  are  not  dead,  but 
in  a  state  of  temporary  repose ;  and  if  a  new  sup- 
ply of  nutritive  material  is  added  to  the  liquid, 
they  are  seen  to  multiply  anew,  until  this  has  been 
exhausted  (Cohn). 


PLATE  n. 


tfC>  •' 


^V  * "'  *•***/»*  •      - 1^ 


'tW 


FIG.   i. 


FIG.  5. 


PLATE  II. 

DIFFERENT  MODES  OF  GROUPING. 

Photo-micrographs  by  Dr.    Sternberg. 

FIG.  1.  —  Torula  form  of  spherical  bacteria  (Micoderma  aceli 
Pasteur)  from  rotten  banana,  New  Orleans,  April,  1880.  X  1000 
diameters  by  Zeiss's  ^  in.  objective. 

FIG.  2.  —  Zooyloea  ramiqera  from  surface  of  foul  gutter-water. 
Baltimore,  1880.  X  1000*  diameters. 

FIG.  3.  —  Zooglaaform  of  spherical  bacteria  developed  in  culture- 
cell  containing-  blood  of  leper.  X  600  diameters. 

FIG.  4.  —  Mycoderma,  from  surface  of  foul  gutter-water.  New 
Orleans,  April,  1880.  X  400  diameters  by  Beck's  i  in.  objective. 

FIG.  5.  —  Leptothrix  chain  of  Bacilli  (B.  w?na°?)  from  putrid 
blood  of  yellow-fever  patient  obtained  post  mortem.  X  3000  diam- 
eters. (Seep.  261). 


CHAPTER  II. 
CLASSIFICATION  OF  THE  BACTEKIA. 


§  1. — POSITION  OF  THE  BACTERIA. 

THE  place  of  the  bacteria  in  the  scale  of  beings, 
for  a  long  time  undetermined,  demands  to  be 
established  with  precision ;  not  only  for  the  natu- 
ralists, who  only  view  the  question  from  a  system- 
atic point  of  view,  but  above  all  for  the  biologists 
who  study  the  role  of  these  organisms  in  the  chem- 
ical or  pathological  phenomena  with  which  they 
are  associated.  According  to  Ch.  Robin,  not  to 
define  the  animal  or  vegetable  nature  of  these 
organisms,  "  is  for  them  as  grave  as  it  would  be  for 
a  chemist  to  leave  undecided  the  question  as  to 
whether  it  was  nitrogen  or  hydrogen,  urea  or 
stearine,  which  he  had  obtained  from  a  tissue,  or  of 
which  he  is  following  the  combinations  in  certain 
operations." 

This  determination  is,  to-day,  possible ;  and,  if 
there  are  still  some  differences  of  opinion  among 
naturalists  as  to  the  place  of  the  bacteria  among 
the  cryptogams,  there  is  but  one  opinion  as  to 
their  vegetable  nature. 

It  is  surprising  to  see  a  savant  like  M.  Pasteur 
"  not  to  pronounce  positively  upon  the  vegetable 


CLASSIFICATION  OF  THE  BACTERIA.  49  • 

or  animal  nature  of  several  of  the  ferments  which 
he  has  studied,"  and  of  which  some  belong  to  the 
bacteria. 

We  shall  first  indicate  rapidly  the  characters 
which  permit  us,  at  first,  to  recognize  certain  spe- 
cies of  bacteria  as  organized  beings,  to  determine 
if  they  are  animal  or  vegetable,  and  finally  to 
classify  them  either  among  the  algae  or  among  the 
fungi. 

Distinction  of  Bacteria  from  Inorganic  Sub- 
stances. —  The  question  as  to  whether  bacteria  are 
organized  beings  can  only  be  raised  in  relation  to 
the  smallest  species,  those  Micrococci  which  are 
scarcely  perceptible  with  the  highest  powers  ;  the 
organized  nature  of  the  other  organisms  of  the 
same  group  has  never  been  questioned,  even  by 
the  earliest  observers,  who  all,  since  Leeunhoeck, 
have,  without  exception,  taken  them  for  animals 
or  vegetables.  But  the  smallest  forms  of  bacteria 
may  be  confounded  with  various  matters,  with 
organic  particles,  molecular  granules,  fat  globules, 
etc.  "  These  productions,  which  are  found  in  con- 
siderable quantity  in  the  liquids  or  in  the  tissues 
of  animal  or  vegetable  origin,  often  resemble  so 
closely,  in  form,  size,  and  grouping,  the  spherical 
bacteria,  that  it  is  absolutely  impossible  to  guard 
one's  self  against  confusion,  unless  the  most  mi- 
nute precautions  are  taken  in  making  the  observa- 
tions "  (Cohn). 

The  detritus,  the  amorphous  powder  of  precipi- 
tated molecules  of  inorganic  substances,  even  when 


50  MORPHOLOGY  OF  THE  BACTERIA. 

they  exhibit  the  brownien  movement,  are  easily 
enough  distinguished  from  fificrococci  by  optical 
signs,  their  angular  form,  their  less  refractive 
power,  and  finally  by  their  reaction  with  certain 
chemical  agents;  above  all  if  they  are  mineral 
substances,  crystalline  bodies,  etc. 

It  will  not  be  the  same  with  molecular  granules 
of  organic  nature.  They  have  as  common  charac- 
ters, their  rounded  form,  their  notable  refractive 
power,  movements.  Nevertheless,  their  form  is 
less  regular,  more  angular,  their  color  variable,  their 
refractive  power  always  less.  In  doubtful  cases, 
Tiegel  has  given  a  method  which  enables  us  to  dis- 
tinguish them  from  Micrococci.  It  consists  in 
warming  the  glass  slide  which  supports  the  cor- 
puscles under  examination  ;  if  they  are  "  Cbccos," 
they  are  seen  to  move  in  a  manifest  manner. 
This  does  not  occur  in  the  case  of  molecular  gran- 
ules. 

It  is  these  productions  which  render  it  very 
difficult  to  observe  the  phenomena  which  occur 
during  the  coagulation  of  milk.  The  caseine  sep- 
arates in  the  form  of  extremely  minute  globules 
"having  a  very  rapid  molecular  movement.  But 
we  may  distinguish  these  from  bacteria  by  the 
use  of  liquor  potassse,  which  dissolves  the  former 
without  attacking  the  latter. 

As  another  example  of  pseudobacteria,  I  will 
mention,  after  Cohn,  the  form  which  fibrine  as- 
sumes when  it  separates  from  the  plasma  of  the 
blood.  It  disposes  itself  in  very  slender  filaments, 
closely  resembling  filamentous  bacteria. 


CLASSIFICATION   OF  THE   BACTERIA.  51 

Fat  globules,  which  are  found  of  all  sizes,  are 
often  of  the  same  dimensions  as  Micrococcus,  and 
are  very  difficult  to  distinguish  from  the  latter. 
The  difference  in  refractive  power  is  slight,  and 
the  action  of  re-agents,  such  as  ether,  is  not  cer- 
tain in  mucilaginous  solutions.  Hiller,  who  has 
paid  especial  attention  to  the  means  of  recognizing 
bacteria,  divides  them  into  two  groups :  — 

A.  The  optical  signs:  comprising  1.  The  charac- 
teristic vegetable   form,  rods,  leptothrix,  this   he 
recognizes  as  of  little  use,  as  in  this  case  there  is 
no  doubt;  2.  The  characteristic  movements  of  the 
monads;   3.  The  mode  of  growth  and  of  multipli- 
cation ;  4.  The  mode  of  junction  of  the  granules. 

B.  The  chemical  signs  :  1.  False  zooglcea  become 
softened    and    diffluent   under   the   action  of   liq. 
potassse,  and  are  coagulated  by  the  direct  applica- 
tion of  alcohol ;  2.  In  sections  of  tissues,  after  an 
hour  of  maceration  in  liq.  potassse,  diluted  -^th, 
the  monads  are  colored  brown  by  iodine,  while  fat 
granules  are  not. 

But,  in  truth,  the  method  of  cultivation,  ex- 
tolled by  Cohn  and  Wolff,  is  the  best  means  of 
distinguishing  the  bacteria.  "  The  distinction  of 
pseudobacteria,"  says  the  first  of  these  authors, 
"  from  veritable  globular  bacteria  is  a  problem 
which  our  microscopists  cannot  resolve,  in  every 
case,  with  the  desirable  certainty.  It  is  only  by 
a  study  of  their  mode  of  development  that  this 
distinction  can  be  made.  The  globules  which  di- 
vide and  develop  in  form  of  chains  are  organized 
beings ;  when  this  does  not  occur,  we  are  dealing 
with  pseudobacteria." 


52  MORPHOLOGY  OF  THE  BACTERIA. 

This  is  not,  however,  exactly  the  opinion  of 
Nageli,  who  seems  to  consider  movement  as  the 
surest  distinctive  characteristic. 

"  There  are,"  he  says,  "  but  three  distinctive 
signs  which  enable  us  to  recognize  with  some 
certainty  that  granules  under  observation  are  or- 
ganisms, —  spontaneous  movement,  multiplication, 
and  equality  of  dimensions,  united  with  regularity 
of  form. 

"The  most  certain  character  is  movement  in 
a  straight  or  curved  line,  —  a  movement  which 
inorganic  granules  never  present.  One  should 
take  care  not  to  be  deceived  by  movements 
which  are  caused  by  currents  in  the  liquid  under 
observation.  Nor  should  one  allow  himself  to  be 
deceived  by  the  tremulous  motion,  called  molecu- 
lar movement,  in  which  the  granules  do  not  really 
change  their  position.  These  movements  are  seen 
in  most  cells,  and  even  in  those  of  the  Schizomy- 
cetes,  and  inorganic  bodies  themselves  present  it. 

"  Multiplication  is  a  character  less  important 
than  movement.  When  among  granules  some 
are  found  united  in  pairs,  it  may  be  supposed 
with  probability  that  division  and  multiplication 
are  taking  place.  When  rods  are  bent  at  an  angle, 
one  may  predict  their  division  in  two  parts. 

"  Finally,  as  to  size  and  form.  Granules  of  dif- 
ferent size  and  of  a  more  or  less  irregular  form 
ought  not  to  be  considered  as  belonging  to  the 
group  of  segmented  fungi ;  if,  on  the  contrary, 
the  granules  offer  dimensions  perfectly  equal,  and 
a  spherical  or  oval  form,  the  distinction  is  more 


CLASSIFICATION  OF  THE  BACTERIA.  53 

uncertain :  they  may  belong  to  the  schizomycetes 
or  be  of  inorganic  nature." 

Place  of  the  bacteria  among  organized  beings. 
Distinction  between  animals  and  vegetables.  —  The 
characters  which  serve  to  distinguish  the  inferior 
animal  organisms  from  the  inferior  vegetable  or- 
ganisms are  of  two  orders,  optical  and  chemical. 

A.  The  optical  characters  are  drawn  from  the 
general  form,   the  movements,  and  the  mode  of 
reproduction. 

The  morphological  characters  have  no  value 
except  among  the  larger  species  of  bacteria.  If 
we  bring  together  a  Spirillum  and  &Spindina, 
Kiitz.,  their  affinities  will  be  apparent  to  every 
one.  It  is  not  the  same  for  the  large  species  of 
Bacillus,  of  which  the  relations  with  the  Oscilla- 
toria  are  evident.  The  rod  form  seems  very  spe- 
cial, but  it  does  not  necessarily  imply  the  vege- 
table nature  of  the  organisms  which  possess  it. 
Finally,  the  spherical  bacteria,  —  Monas  and  Mi- 
crococcus,  —  resemble  entirely  by  their  form  some 
infusorial  animals. 

Movement  is  not  a  more  special  character.  It 
is  now  well  proved  that  it  does  not  belong  exclu- 
sively to  animals,  and  that  it  is  met  with  in  a  cer- 
tain number  of  the  inferior  vegetables. 

In  fact,  the  anatomical  characters  are  not  al- 
ways absolutely  reliable ;  but  it  is  from  these 
alone  that  Cohn  first,  then  Davaine,  have  recog- 
nized the  bacteria  as  vegetables. 

B.  Chemical   characters.     Robin  depends  upon 


54       MORPHOLOGY  OF  THE  BACTERIA. 

these  characters  to  demonstrate  the  vegetable  na- 
ture of  the  bacteria.  He  takes  for  point  of  de- 
parture the  notions  of  general  physiology  as  given 
by  De  Blainville  in  the  following  points :  — 

1.  We  find  in  animals  various  elementary  sub- 
stances of   the  same  kind   as   in  plants,  and  re- 
ciprocally. 

2.  The  ternary  compounds   predominate.,  how- 
ever, in  plants ;  and  the  quarternary,  nitrogenized, 
are  more  abundant,  on  the  contrary,  in  animals. 

3.  In  both,  the  fundamental  cellular  structure 
is   the  same ;   at  least  originally  for  the  greater 
number,  and  always  in  the  most  simple  of  organ- 
ized beings,  etc.  .  .  . 

"  It  results  from  this,  then,"  continues  M.  Kobin, 
"  that  so  long  as  there  is  no  digestive  tube  one 
can  only  distinguish  plants  from  animals  by  the 
study  of  their  elementary  principles,  and  of  the 
chemical  reactions  which  these  exhibit  in  general ; 
by  the  study,  in  particular,  of  the  reactions  which 
the  predominance  of  ternary  cellulose  principles 
over  all  others  gives  to  plants,  and  that  of  nitro- 
genized principles  in  animals,  at  all  periods  of 
their  existence." 

Starting  from  this  basis,  Robin  made  numerous 
attempts  to  find  in  liquor  ammonia,  concentrated, 
as  prepared  for  use  in  laboratories,  a  reagent  for 
corpuscles  of  a  vegetable  nature.  In  effect,  am- 
monia dissolves  the  eggs,  the  embryos,  of  all  ani- 
mals, the  bodies  of  all  the  inferior  infusoria, 
attacks  the  spermatozoa,  etc.,  whilst  it  leaves  ab- 
solutely intact  all  the  varieties  of  cellulose  and 


CLASSIFICATION  OF  THE  BACTERIA.  55 

the  anatomical  reproductive  elements  of  plants, 
whether  it  is  used  cold  or  boiling. 

As  to  the  other  chemical  characters  praised 
during  recent  years,  we  will  content  ourselves 
with  mentioning  concentrated  acetic  acid,  which 
causes  all  animal  tissues  to  become  pale,  whilst  it 
is  without  action  on  bacteria  (Luckonvsky) ;  io- 
dine, and  sulphuric  acid  (Letzerich),  etc. 

Hematoxyline  (Luckonvsky)  and  fuchsin  (Hoff- 
mann) color  the  bacteria  deeply.  One  ought,  then, 
no  longer  to  give  to  the  bacteria,  as  do  some 
recent  authors,  the  names  of  microscopic  ani- 
malcules, —  infusoria,  microzoa,  etc.,  and  other 
expressions  without  precision,  or  consecrating  an 
error. 

Let  us  add  that  some  naturalists  of  high  re- 
pute, Hackel  for  example,  have  created  for  these 
minute  beings,  monera,  protoplasts,  flagellata,  dia- 
toms, etc.,  an  intermediary  kingdom  between  the 
animal  and  vegetable,  —  the  Protista. 

Place  of  the  Bacteria  in  the  Vegetable  Series.  — 
The  vegetable  nature  of  the  bacteria  once  estab- 
lished, it  remains  now  to  determine  to  what  class 
of  vegetables  they  belong. 

Are  they  algae,  or  are  they  fungi  ?  This  is  the 
question  which  divides  the  naturalists. 

It  is  true  that  it  is  to-day  very  difficult  to  find 
a  characteristic  of  these  two  classes  of  vegetables, 
both  having,  in  a  general  manner,  identical  forms, 
similar  reproductive  apparatus,  etc. ;  and,  if  it  is 
impossible  to  confound  a  Basidiomycete  with  a 
Floridese,  for  example,  it  is  not  the  same  when 


56        MORPHOLOGY  OF  THE  BACTERIA. 

one  studies  the  inferior  species.  The  only  char- 
acter which  appears  general  is  the  presence  of 
chlorophyll  in  the  algae  and  its  absence  in  the 
fungi.  But,  if  we  adopt  this  distinctive  character, 
and  apply  it  in  all  its  rigor,  we  are  obliged  to 
separate  in  the  inferior  algae  some  forms  very 
nearly  related,  and  which  do  not  differ  from  their 
relations  except  in  this  particular.  And  this  is  ex- 
actly what  happens  in  the  case  of  the  bacteria. 

In  truth,  the  bacteria,  although  entirely  with- 
out chlorophyll,  have  numerous  affinities  as  to 
form,  movement,  etc.,  with  the  osciUatoriacece, 
and,  according  as  one  or  the  other  of  these  char- 
acters have  appeared  to  predominate,  the  bacteria 
have  been  classed  as  algae  or  as  fungi. 

It  is  thus  that  Davaine,  Rabenhorst,  then  Cohn, 
struck  above  all  by  the  resemblance  of  form,  mode 
of  grouping,  and  of  multiplication,  have  placed 
the  bacteria  among  the  algae.  Cohn  insists,  above 
all,  upon  the  affinities  of  the  filiform  bacteria  with 
the  beggiatoa  and  the  leptothrix  ;  of  the  micrococ- 
cus,  and  of  the  bacterium,  with  the  chroococcacece. 
He  at  first  placed  them  at  the  commencement  of 
this  last  series ;  but  we  shall  see  further  on  that 
in  his  last  publications  he  has  disseminated  them 
among  the  oscillatoriaceae  and  the  chroococcaceae. 

Robin  and  Nageli,  on  the  other  hand,  insist 
rather  upon  the  affinities  of  the  bacteria  with  the 
yeast  plants,  which  are  incontestably  fungi,  and 
they  include  them  in  this  class. 

Robin  says  expressly :  "  All  the  corpuscles  de- 
scribed under  the  name  of  Bacterium  termo,  B. 


CLASSIFICATION  OF  THE  BACTERIA.  57 

punctum,  etc..  Zooglcea,  Micrococcus,  and  many 
others,  are  vegetable  cells,  spores  of  fungi,  of  sev- 
eral distinct  species  certainly;  spores,  or  repro- 
ductive bodies  of  the  first  order,  derived  one  from 
another,  either  by  germination,  fission,  or  from  a 
mycelium ;  reproductive  bodies,  in  a  word,  of  the 
order  of  those  which  Tulasne  has  arranged  under 
the  name  of  conidia,  etc." 

Nageli  establishes  in  the  inferior  fungi  which 
produce  decompositions  three  very  natural  groups. 

1.  The  Mucorini,  or  mould  fungi ; 

2.  The  Saccharomycetes,  or  budding  fungi,  which 
produce  the  fermentation  of  wine,  beer,  etc. ; 

3.  The  Schizomycetes,  or  fission  fungi,  which  pro- 
duce putrefactive  processes.    This  last  group  is  formed 
of  our  bacteria  (Micrococcus,  Bacterium),  etc. 

Sachs  solves  the  question  by  uniting  the  algae 
and  fungi  in  a  single  group,  the  thattophytes,  in 
which  he  establishes  two  series  exactly  parallel, — 
one  comprising  the  forms  with  chlorophyll ;  the 
other,  the  forms  which  are  deprived  of  it,  and 
preserving  in  a  transverse  direction  the  morpho- 
logical affinities  of  these  organisms. 

As  this  classification  is  yet  but  little  known,  we 
think  it  best  to  give  it  in  the  following  table  :  — 

THALLOPHYTES. 

Forms  with  chlorophyll.  Forms  without  chlorophyll. 

CL.  1.  PEOTOPHYTES. 

*    A.  Cyanophycese  (Oscil-    A*.  Schizomycetes  (Bac- 

latoiiacese,  etc.).  teria). 

B.  Palmellaceae.  B'.  Saccharomycetes 

(Ferments). 


PLATE  III. 


Bacillus  subtilis  and  spores  of  bacilli.     Photo-micrographs  by  Dr. 
Sternberg. 

FIG.  1.  —  Spores  of  B.  subtilis  and  micrococci,  from  surface 
culture  on  gelatine  and  beef  peptone.  X  500  diameters. 

FIG.  2.  —  Development  of  bacilli  from  spores,  from  culture  ex- 
periment with  fish  gelatine  solution.  X  1,500  diameters  by  Zeiss's 
^  in.  objective. 

FIG.  3.  —  Spores  of  Bacillus  developed  in  rotten  potato,  New 
Orleans,  April,  1880.  X  1,500  by  Zeiss's  ^  in.  objective.  The 
large  cells  are  some  species  of  Saccharomycete,  which  was  also 
present  in  the  same  specimen. 

FIG.  4.  —  Bacillus  (B.  ulna}  containing  a  single  spore  at  one  ex- 
tremity ;  from  putrid  blood  (of  yellow- fever  patient)  obtained  post 
mortem.  X  3000  diameters. 

FIG.  5. — Bacillus  subtilis,  from  surface  of  beef -peptone  culture- 
solution.  X  500  by  Zeiss's  £  in.  objective  (D.  D.,  dry);  Balti- 
more, 1884. 


PLATE  in. 


FIG.   i 


FIG.  2. 


CLASSIFICATION  OF  THE  BACTERIA.          .59 

CL.  2.  ZYGOSPOREJE. 

A.  Volvocinese.  A'.  Myxomycetes. 

B.  Conjugueae  and  Dia-     B'.  Zygomycetes. 
toms. 

CL.  3.  OOSPOREJE. 

A.  Sphseroplese. 

B.  Cceloplastese.  Saprolegnise. 

C.  (Edogonise.  Peronosporese. 

CL.  4.  CARPOSPORE.E. 

A.  Coleochsetese.  A'.  Ascomycetes. 

B.  Floridese.  B'.  GEcidiomycetes. 

C.  Characese.  C'.  Basidiomycetes. 

Our  preferences  are  for  this  last  mode  of  classi- 
fication, but  obliged,  in  the  description  of  species, 
to  follow  the  classification  of  Cohn,  the  most  com- 
plete which  has  been  given  hitherto,  we  must 
abandon  it  for  the  present. 

§  2.  —  CLASSIFICATION  ;  GENERIC  AND  SPECIFIC 
CHARACTERS. 

The  numerous  classifications  of  the  bacteria  of 
which  we  have  given  an  abstract  in  the  historical 
part  of  this  work,  show  how  variable  have  been 
the  ideas  of  the  microscopists  as  to  the  nature  of 
these  organisms. 

Before  giving  the  most  recent,  those  among 
which  we  will  have  to  choose,  it  is  best  to  study 
the  characters  upon  which  authors  have  depended 
for  grouping  the  bacteria  in  genera  and  species, 
and  to  estimate  the  value  of  these  characters. 


60  •      MORPHOLOGY  OF  THE  BACTERIA. 

1.  Generic  and  specific  characters. —  These  have 
been  drawn  from  the  dimensions,  form,  movement 
and  evolution  of  the  bacteria. 

The  size,  which,  according  to  Cohn,  is  the  dom- 
inating distinctive  character,  is  often  indetermi- 
nable, even  in  employing  the  highest  powers. 
Besides,  for  a  great  number  of  neighboring  forms, 
the  differences  of  measurement  given  as  distinctive 
are  so  slight  that  they  cannot  serve  in  practice. 
Thus,  according  to  Dujardin,  the  Bacterium  termo 
has  a  length  of  1.7  /A,  and  iheJB.punctum  of  1.7  to 
0.6  JJL.  Another  difficulty  presents  itself  when  we 
examine  bacteria  formed  of  several  articles.  Shall 
we  consider  the  length  of  a  single  article  or  of  the 
chain,  which  consists  of  a  number  of  articles,  a 
number  ordinarily  variable  ? 

The  form  of  the  bacteria  and  their  union  in 
colonies,  also  offer  differences,  which  have  been 
utilized ;  but  do  they  depend  upon  differences  truly 
specific,  or  do  they  come  from  foreign  influences, 
from  phases  of  development  of  the  same  organism? 
Even  when  one  uses  these  as  distinctive  specific 
characters,  the  form  is  sometimes  of  little  assist- 
ance ;  since  if  one  refers  to  the  descriptions  of 
Dujardin,  the  Bacterium  termo  will  be  found  to  have 
a  cylindrical  body  swollen  in  the  middle,  and  the 
B.  punctum  an  elongated  ovoid  body. 

As  to  movement,  we  have  seen  that  the  phenom- 
ena of  mobility  or  of  immobility  sometimes  pre- 
sent themselves  in  the  same  species,  according  to 
age  or  changes  in  the  medium. 

We  have  left,  the  mode  of  development,  the 


CLASSIFICATION  OF  THE  BACTERIA.  61 

phenomena  of  reproduction  by  fission  or  by 
spores,  as  the  only  character  which  can  serve  to 
establish  our  natural  genera;  but,  unfortunately, 
this  has  only  been  ascertained  for  a  small  number 
of  bacteria,  the  Bacillus  anthracis,  for  example. 

The  genera  of  bacteria  cannot  have  the  same 
significance  as  among  animals  and  superior  vege- 
tables ;  they  can  only  be  established  in  accordance 
with  the  most  prominent  characters,  reserving  the 
feeble  modifications  of  these  generic  forms  as 
specific  characters. 

Are  there  distinct,  well-defined)  species  among 
the  Bacteria  f 

The  microscopists  have  given  the  most  diverse 
opinions  upon  this  subject.  Miiller,  Ehrenberg, 
Dujardin,  Davaine,  have  admitted  the  specific  dis- 
tinction of  the  numerous  vibrioniens  which  they 
have  described.  Davaine,  however,  raises  some 
doubts  as  to  the  absolute  value  of  the  species 
established  in  his  time.  "  Those  which  are  de- 
scribed to-day  by  the  classifiers,"  he  says,  "  ought 
to  be  considered  as  the  expression  of  types  under 
which  are  hidden  a  certain  number  of  distinct 
species." 

Cohn  dwells  still  more  upon  the  impossibility, 
in  which  we  are  to-day,  of  distinguishing  with 
certainty  genera  and  species  among  the  bacteria. 
However,  he  is  convinced  that  the  bacteria  are  di- 
vided into  species  as  distinctly  as  the  other  plants 
and  inferior  organisms.  It  is  only  the  imperfection 
of  our  means  of  observation  which  makes  it  impos- 
sible to  recognize  these  differences.  This  is  above 


62  MORPHOLOGY  OF  THE  BACTERIA. 

all  true,  he  says,  of  the  spirilla,  which  are  not  only 
distinguished  from  the  rod  bacteria,  properly  so 
called ;  but  which  present  in  their  species  some 
differences  as  constant  as  any  well-defined  species 
of  alga  or  of  infusoria. 

Hallier,  Hoffmann,  Billroth,  Robin,  Nageli,  etc., 
consider  the  different  forms  of  bacteria  in  a  very 
different  fashion.  According  to  them  they  are 
not  autonomous  species,  but  phases  of  development 
of  one  or  of  several  species. 

According  to  Hallier,  we  may  see,  a  propos  of 
the  polymorphism  of  the  bacteria,  the  singular 
transformations  which  he  has  obtained  by  their 
cultivation. 

-According  to  Billroth,  the  bacteria  belong  to  a 
single  species  of  plants,  the  Coccobacteria  septica, 
with  the  exception  of  the  Spirillum  and  Spirochceta, 
in  regard  to  which  Billroth  is  not  willing  to  give 
an  opinion.  This  view  has  been  adopted  by  a 
certain  number  of  microscopists,  and  above  all  by 
the  pathologists,  such  as  Frisch,  Tiegel,  etc. 

Robin  also  admits  the  genetic  relation  of  Micro- 
coccuSj  Vibrio,  Bacterium  and  Leptothrix,  but  con- 
siders them  the  distinct  and  successive  phases  in 
the  evolution  of  several  species :  1st.  Corpuscles 
described  under  the  name  of  Bacterium  termo, 
punctum,  etc.,  Micrococcus ;  2d.  Mycelial  fila- 
ments, Vibrio,  etc. ;  3,  Bacteria,  Bacteridies,  Micro- 
bacteria,  etc. ;  4th.  Leptothrix  and  forms  more 
advanced. 

The  opinion  of  Nageli  corresponds  very  nearly 
with  the  preceding.  "  As  much  as  I  am  con- 


CLASSIFICATION  OF  THE  BACTERIA.  63 

vinced,"  he  says,  "  that  the  schizomycetes  cannot 
be  grouped  in  accordance  with  their  action  as  fer- 
ments and  their  exterior  forms,  and  that  altogether 
too  many  species  have  been  distinguished  ;  so,  on 
the  other  hand,  it  seems  to  me  very  improbable 
that  all  the  schizomycetes  constitute  a  single  natu- 
ral species. 

"  I  am  rather  inclined  to  suppose  that  there  exists 
among  them  a  small  number  of  species,  which 
have  little  in  common  with  the  genera  and  species 
admitted  to-day,  and  of  which  each  runs  through  a 
cycle  of  determined  forms  sufficiently  numerous. 
Each  of  the  veritable  species  of  schizomycetes  is 
not  limited  to  presenting  itself  under  the  different 
forms  of  Micrococcus,  Bacterium,  Vibrio,  and  Spi- 
rillum, but  can  also  show  itself  as  the  agent  of 
acidification  of  milk,  of  putrefaction,  and  as  the 
agent  producing  several  maladies."  However, 
Nageli  recognizes  that  it  is  necessary  to  distin- 
guish these  forms,  notably  those  of  Micrococcus, 
Vibrio,  Bacterium,  and  Spirillum,  without,  how- 
ever, losing  from  view  the  fact  that  the  organisms 
thus  classified  have  a  very  inconstant  constitution, 
and  pass  continually  from  one  form  to  another. 

Finally,  other  savants  such  as  M.  Pasteur,  take 
less  account  of  the  structural  characters  than  of 
the  physiological  functions,  regarding  as  a  partic- 
ular species  every  form  of  bacterium  .which  is  born 
constantly  in  a  determined  medium,  or  which 
causes  a  special  kind  of  fermentation. 

Nageli  opposes  to  this  view  the  following 
objections.  First,  he  has  verified  the  presence,  in 


64        MORPHOLOGY  OF  THE  BACTERIA. 

the  same  decomposition,  of  several  different  forms 
of  schizomycetes.  On  the  other  hand,  in  decom- 
positions quite  different,  we  may  observe  schizo- 
mycetes entirely  similar  as  to  their  exterior  form. 
Finally,  we  may  change  the  mode  of  action  of  a 
schizomycete  in  subjecting  it  to  a  certain  treat- 
ment. One  sees  that  it  is  truly  difficult  to  form 
an  opinion  as  to  the  value  of  these  species  purely 
physiological. 

To  sum  up,  the  characters  which  may  be  used 
in  order  to  establish  genera  and  species  in  the 
group  of  the  bacteria  are  of  small  number  and  of 
very  unequal  value.  Some,  characters  of  form,  of 
dimension,  of  movement,  etc.,  are  often  difficult  to 
determine,  or  have  only  a  relative  value ;  others, 
characters  drawn  from  development  and  reproduc- 
tion, are  only  known  in  so  few  species  that  they 
cannot  be  made  to  serve  as  a  basis  of  classifica- 
tion. 

One  will  not  be  surprised,  then,  to  find  that 
there  is  no  natural  classification  of  the  bacteria, 
and  that  it  is  impossible  for  the  naturalists  to  give 
one.  All  those  that  can  be  established  are  pro- 
visory, being  only  based  upon  the  morphology  of 
these  organisms.  Following  the  example  of  all  the 
botanists,  we  will  use  an  analogous  classification, 
but  without  wishing  to  prejudge  in  any  particular 
the  genealogical  relationship  of  the  different  or- 
ganisms, which  we  shall  consider  as  distinct  gen- 
era and  species. 


CLASSIFICATION  OF  THE  BACTERIA.  65 


§  3.  —  CLASSIFICATION  AND  DESCRIPTION  OF  THE 
GENERA  AND  SPECIES  OF  THE  BACTERIA. 

We  have  seen  in  the  historical  portion  of  this 
work,  a  propos  of  the  classifications  which  have 
been  given  of  the  bacteria,  that,  in  1872,  M.  Cohn, 
recognizing  the  numerous  relations,  absence  of 
chlorophyll,  mode  of  nutrition,  etc.,  which  make 
these  organisms  a  natural  family,  divided  them 
into  four  tribes  :  — 

1.  The  Spherobacteria,  or  spherical  bacteria. 

2.  The  Microbacteria,  or  B.  in  short  rods. 

3.  The  Desmobacteria,  or  B.  in  straight  filaments. 

4.  The  Spirobacteria,  or  B.  in  spiral  filaments. 

In  the  spherobacteria,  Cohn  has  only  adopted 
one  genus,  the  g.  Micrococcus,  of  which  the  spe- 
cies are  divided  into  three  series,  —  the  pigmen- 
tary M.,  or  chrornogenes,  the  M.  of  fermentations, 
or  zymogenes,  and  the  M.  of  contagious  affections, 
or  pathogenes. 

The  microbacteria  include  only  the  genus  Bac- 
terium, with  two  species,  B.  termo,  Dujardin,  and 
B.  lineola,  Cohn. 

The  desmobacteria  comprehend  the  g.  Bacillus 
and  Vibrio  ;  the  first  established  by  Cohn  for  the 
rectilinear  filaments  is  composed  of  the  B.  subtilis, 
Cohn  (with  B.  anthracis  as  a  variety)  and  the  B. 
ulna,  Cohn ;  the  second,  characterized  by  undu- 
lating filaments,  is  reduced  to  V.  rugula  and  ser- 
pens}  Auct. 


66       MORPHOLOGY  OF  THE  BACTERIA. 

Finally,  the  spiral  filaments  of  the  spirobacte- 
ria  characterize  the  gr.  Spirillum  and  Spirochceta, 
which  might  be  united  in  a  single  genus  compris- 
ing Sp.  plicatile,  tenue,  undula,  and  volutans. 

Since  then,  Cohn,  struck  with  the  affinities 
which  each  of  the  preceding  genera  presents  with 
several  genera  of  oscillatoriacese  and  of  chroococ- 
ceae,  from  which  the  bacteria  only  differ  by  the 
absence  of  chlorophyll,  has  established  a  class  of 
Schizophytes,  which  includes  all  the  inferior  vege- 
table organisms,  provided  or  not  with  chlorophyll, 
multiplying  by  fission. 

We  give  below  the  complete  table :  — 


2.  Classification  of  the  Schizophytes,  Cohn. 
TRIBE   1.  —  GL^OGENES. 

Cells  free  or  united  in  glairy  families  by  an  intercellular  substance. 

A.  Cells  free  or  united  by  2  or  by  4  : 

Cells  spherical   .     .  CHROOCOCCUS,  Nag. 
Cells  cylindrical     .  SYNECHOCOCCUS,  Nag. 

B.  Cells  united  in  glairy  families, 

amorphous  in  state  of 
repose  : 

a.  Cellular  membrane,   con 
founded  with  the  intercel- 
lular substance :' 
1.  Cells  without  phyco- 
chrome,  very  small : 
Cells  spherical   .    .  MiCROCOCCUS,  Hallier. 


CLASSIFICATION   OF  THE   BACTERIA.  67 

Cells  cjdindrical     .  BACTERIUM,  Duj. 
2.  Cells  with  phyco- 
chrome,  larger : 

Cells  spherical   .     .  APHANOCAPSA,  Nag. 
Cells  cylindrical     .  APHANOTHECE,  Nag. 
I.  Intercellular   substance 
formed   of    several    mem- 
branes enclosed  one  with-  • 
in  the  other : 

Cells  spherical   .     .  GLCEOCAPSA,  Kg. 
Cells  cylindrical     .  GLCEOTHECE,  Nag. 

C.  Cells  united  in  glairy  fam- 
ilies of  definite  form : 
a.  Families  of  a  single  layer 
of  cells  disposed  in  plates : 

1.  Cells   in   fours   form- 
ing a  plane  surface     .  MERISMOPEDIA,  Meyeii. 

2.  Cells  without  regular 
arrangement,  forming 
a  curved  surface : 

Cells  spherical,  fam- 
ilies with  reticu- 
lated rupture  .     .  CLATHROCYSTIS,  Henfr. 
Cells  cylindrical,  cu- 
neiform,  families 
divided    by   con- 
striction     .      .      .   CaSLOSPBLERITJM,  Nag. 
I  Families  with  several  lay- 
ers of  cells,  united  in  spher- 
ical corpuscles : 

1.  Number  of  cells  de- 
termined : 

Cells  spherical,  col- 
orless, arranged 
in  fours  .  .  .  SARCINA,  Goods. 


G8  MORPHOLOGY  OF  THE  BACTERIA 

Cells  cylindrical,  cu- 
neiform, with  phy- 
cochrome,    with- 
out   regular    ar- 
rangement      .      .  GoMPHOSPH^EilA,  Kg. 
2.  Number  of  cells  very 
great  and  indetermi- 
nate : 

Cells  colorless,  very 
small     ....  Ascococcus,  Billr. 


Cells    colored    by 
phycochrome 
and  larger .     . 


POLYCYSTIS,  Kg. 

COCCOCHLORIS,  Spr. 

POLYCOCCUS,  Kg. 


TRIBE  2.  — NEMATOGENES. 

Cells  disposed  in  filaments. 

A,  Filaments  not  branched : 
a.  Filaments    free    or    inter- 
laced. 

1.  Filaments  cylindrical, 
colorless,  articulations 
not  very  distinct : 

Filaments  very  slen- 
der, short  .     .     .  BACILLUS,  Cohn. 

Filaments  very  fine, 
long LEPTOTHRIX,  Kg. 

Filaments  larger, 

long      ....  BEGGIATOA,  Trev. 

2.  Filaments  cylindrical,  \ 
with  phycochrome, 


articles  well  denned, 


,    OSCILLARIA,  BOSC. 

without  cellular  re- v 
production    .     .     . 


HYPHEOTHRIX,  Kg. 


CLASSIFICATION  OF  THE  BACTERIA.  69 

3.  Filaments  cylindrical, 
articulated,   with    co- 
nidia : 

Filaments  colorless    CRENOTHRIX,  Colin. 
Filaments  with  phy- 
cochrome  .     .     .  CHAM^ESIPHON. 

4.  Filaments  spiral 
without  phycochrome : 

Filaments,  short, 
light,  sinuous      .  VIBRIO,  Ehr. 

Filaments,  short,  spi- 
ral, rigid    .    .     .  SPIRILLUM,  Ehr. 

Filaments,  long,  spi- 
ral, flexible     .     .  SPIROCH^TE,  Ehr. 
with  phycochrome : 

Filaments  long,  spi- 
ral, flexible     .    .  SPIRULINA,  Link. 

5.  Filaments  in  chaplet : 
Filaments,  without 

phycochrome      .     .  STREPTOCOCCUS,  Billr. 
Filaments  with  phy- )  ANABJSNA,  Bory. 
cochroine  .    .    .     j  SPERMOSIRA,  Kg. 

6.  Filament  flagelliform,     . 

slender MASTIGOTHRIX,  etc. 

b.  Filaments  united  into  glai- 
ry families  by  an  intercel- 
lular substance : 

1.  Filaments  cylindrical, 

colorless MYCONOSTOC,  Cohn. 

2.  Filaments     cylindri- 


cal, with  phyco- 
chrome 


CHTHONOBLASTUS. 

LlMNOCLIDE,  Kg. 


3.  Filaments  in  chaplet .  NOSTOC,  etc. 
4  Filaments  flagelliform, 

slender RIVULARIA,  etc. 


70        MORPHOLOGY  OF  THE  BACTERIA. 

B.  Filaments  with  false  ramifi- 
cation : 

1.  Filaments    cylindri-  j  CLADOTHRIX,  Cohn. 
cal,  colorless      .     .     )  STREPTOTHRIX,  Cohri. 

2.  Filaments     cylindri- 


cal, with  phyco- 
. chrome     .     .     . 


CALOTHRIX,  Ag. 

SCYTONEMA,  Ag. 


3.  Filament  in  chaplets  .  MERIZOMYRIA,  Kg. 

4.  Filaments  flagelli-      J  SCHIZOSIPHON)  K 
form.slender  towards     GEOCYC         K 
the  extremity    .     .     ) 

An  inspection  of  this  table  shows  that  each  of 
the  genera  of  the  ancient  group  of  the  bacteria 
has  been  placed  beside  some  genus  of  oscillatori- 
aceoe,  which  it  resembles  by  its  organization, — 
Micrococcus  and  Bacterium,  beside  Aphanotkece 
and  Aphanocapsa ;  Bacillus,  beside  Leptothrix 
and  Beggiatoa ;  Vibrio  and  Spirillum,  beside  Spi- 
rulina. 

These  affinities  are  undeniable,  and  the  advan- 
tages of  such  a  classification  are  manifest ;  but,  in 
a  work  like  this,  we  cannot  think  of  employing  it. 
We  preserve,  then,  in  a  distinct  group  the  schizo- 
phytes  deprived  of  chlorophyll,  which  may  be 
arranged  in  the  four  primary  divisions  of  Cohn 
with  the  exception  of  Sarcina,  Ascococcus,  Creno- 
thrix,  etc.,  and  the  other  genera  created  recently 
by  this  botanist. 

Thus  we  will  describe  successively :  — 

1.  The  Spherobacteria  of  Cohn;  and  beside  them 
the  different  Monas  recently  studied,  —  the  Micrococ- 


CLASSIFICATION  OF   THE  BACTERIA.  71 

cus  described  by  Hallier   in  several  infectious  mal- 
adies. 

2.  The  Microbacteria. 

3.  The  Desmobacteria,  including  Bacillus,  Lepto- 
thrix,  Beggiatoa,  and  Crenothrix. 

4.  The  Spirobacteria,  including  the  three  genera, 
Vibrio,  Spirillum,  and  Spirochceta. 

5.  Finally,  we  will  give  some  account  of  the  Mer- 
ismopedia,  Sarcina,  Ascococcus,   Streptococcus,  Myco~ 
nostoc,  Cladothrix,  and  Streptothrix. 

1.  SPHEROBACTERIA,  Cohn. 

The  spherical  bacteria  are  characterized  by  their 
rounded  or  oval  form,  their  small  size,  often  less 
than  1  fji.  They  are  ordinarily  isolated,  often  in 
pairs  (diplococcus),  sometimes  in  a  chain  of  several 
articles  (streptococcus  =  torula  of  Cohn),  the  my- 
cothrix  of  Hallier  and  Itzigsohn,  or  in  the  form  of 
zooglcea  when  they  are  young  and  actively  multi- 
plying, and  that  of  mycoderma,  when  they  are 
gathered  upon  the  surface  of  liquids.  They  have 
no  spontaneous  movement,  but  a  simple  molecular 
trepidation. 

Functions :  "  The  spherical  bacteria  are  fer- 
ments, not  producing  putrefaction,  but  substitu- 
tions of  another  kind"  (Cohn). 

Obs.  According  to  the  facts  observed  by  Koch, 
Cohn,  Pasteur,  Toussaint,  upon  the  development 
of  certain  bacteria,  it  is  very  probable  that  some 
at  least  of  the  spherobacteria  are  spores  of  Bacil- 
lus or  of  other  bacteria;  at  least,  the  micrococci 
and  these  spores  are  identical  in  form  and  aspect. 


72  MORPHOLOGY  OF  THE  BACTERIA. 

The  spherobacteria  include  only  the  genus  Mi- 
crococcus. 

g.  Micrococcns,  Cohn  (Hallier  emend.  —  Micro- 
sphceria,  Cohn.  ante). 

Cells  colorless,  or  scarcely  colored,  very  small, 
globular  or  oval,  forming  by  transverse  division 
filaments  of  two  or  several  articles,  in  form  of 
chaplet,  or  united  in  numerous  cellular  families, 
or  in  gelatinous  masses,  all  deprived  of  move- 
ment. 

The  species  are  divided  into  three  physio- 
logical groups : — 

a.  M.  Chromogenes. 

b.  M.  Zymogenes. 

c.  M.  Pathogenes. 

SECTION  (A)  :  MICROCOCCUS  CHROMOGENES. 

The  pigmentary  bacteria  grow  in  the  state 
of  Zooglcea  upon  the  surface  of  the  substances 
which  furnish  them  with  nutriment.  They  are 
always  alkaline ;  all  are  avid  of  oxygen ;  their 
morphological  characters  are  identical,  and  one 
can  only  distinguish  them  by  their  different 
coloring  properties. 

According  to  Cohn,  they  are  veritable  spe- 
cies ;  for  1.  Their  pigments  offer  the  greatest 
diversity  as  to  chemical  action  and  by  spectro- 
scopic  analysis,  etc. ;  2.  Each  species  cultivated 
in  the  most  diverse  media  produces  always  the 
same  coloring  matter. 


CLASSIFICATION  OF  THE  BACTERIA.  73 

They  are  divided  into  two  categories,  accord- 
ing as  the  pigment  is  soluble  or  not  in  water. 

1.  Coloring  matter  insoluble. 

M.  Prodigiosus,  Cohn  (Monas  prodigiosa,  Ehrb. ; 
—  Palmella  prodigiosa,  Mont. ;  —  Bacteridium 
prodigiosum,  Schrceter). 

A  red  gelatinous  mass,  pink  carmine,  develop- 
ing upon  cooked  alimentary  substances  placed 
in  damp  air,  never  before  cooking. 

It  has  also  been  observed  in  red  milk,  at- 
tributed incorrectly  to  lesions  of  the  teats, 
etc.  (Cohn). 

M.  luteus,  Cohn  (Bacteridium  luteum,  Schroeter). 

A  yellow  gelatinous  mass  studied  by  Schroeter 
and  Cohn  upon  potatoes. 

2.  Coloring  matter,  soluble. 

M.  aurantiacus,  Cohn  (Bacteridium  auriantiacum, 
Schrceter). 

Little  drops,  or  stains,  more  or  less  extended, 
golden  yelloio,  cultivated  by  Schrceter,  upon 
slices  of  cooked  potato;  by  Cohn,  upon  hard 
white  of  egg. 

M.  chlorinus,  Cohn. 

A  glairy  yellowish-green  pigment  found  upon 
hard  white  of  egg,  not  reddened  by  acids,  but 
loses  its  color. 

M.  cyaneus,  Cohn  (Bacteridium  cyaneum,  Schroe- 
ter). 

Pigment    deep   blue,  observed   by   Schrceter 


74        MORPHOLOGY  OF  THE  BACTERIA. 

upon  cooked  potato,  and  cultivated  by  Cohn  in 
nutritious  solutions.  This  coloring  matter  is 
reddened  by  acids,  and  restored  to  blue  by  al- 
kalies, just  as  that  which  forms  when  lichens 
are  macerated  in  presence  of  ammonia. 

M.  violaceus,  Cohn  (Bacteridium  violaceum,  Schroe- 
ter). 

Violet-blue  masses  or  glairy  stains  formed  of 
elliptical  corpuscles  larger  than  those  of  M.pro- 
digiosus,  observed  first  by  Dr.  Schneider,  then 
by  Schrceter  on  cooked  potato. 

Later,  Cohn  has  described  the  two  following 
new  species  (1876),  which  should  be  included  in 
this  group  : 

M.  Candidus,  Cohn. 

Stains  and  points  ichite  as  snow,  observed 
upon  slices  of  cooked  potato. 

M.  fulvns,  Cohn. 

Little  rust-colored  drops,  consisting  of  cells, 
globular  or  united  in  pairs,  in  a  tenacious  inter- 
cellular substance,  diameter  1.5  /*,  observed  by 
Eidam,  then  by  Kirchner,  upon  horse  dung. 

It  is  also  to  the  genus  Micrococcus  that  we 
must  refer  the  little  globular  bacteria,  gifted 
with  movement,  found  by  Eberth  in  white,  yel- 
low, and  red  perspiration,  and  by  Chalvet  in  the 
pus  on  the  edges  of  certain  wounds,  but  which 
should  not  be  confounded  with  the  blue  color 
produced  by  a  Bacterium. 


CLASSIFICATION  OF  THE  BACTERIA.  75 


SECTION  (B):  MICROCOCCUS  ZYMOGENES. 

Globular   bacteria   producing   fermentations   of 
diverse  nature. 

M.  crepusculum,  Cohn  (Monas  crepusculum,  Ehrb.). 
Globular  cells,  colorless,  developing  in  all  in- 
fusions of  animal  and  vegetable  matter  under- 
going decomposition. 

M.  ureae,  Cohn. 

Oval  cells,  isolated,  diameter  1.5  \L  (Pasteur), 
1.2  to  2  p,  (Cohn)  or  united  by  2,  4,  to  8  (to- 
ruld),  in  a  line,  straight,  curved,  zigzag,  or  even 
in  cross  form.  In  urine,  of  which  it  transforms 
the  urea  into  carbonate  of  ammonia  (Pasteur). 

A  Torula  which  appears  identical  with  the 
preceding  Micrococcus,  produces  the  decomposi- 
tion of  hippuric  acid  into  benzoic  acid  and  gly- 
collamine  (Van  Tieghem). 

M.  of -stringy  wine,  etc. 

Globular  cells  of  2  ^  diameter,  in  chaplets, 
found  in  stringy  wine,  perhaps  identical  with 
the  preceding  (Pasteur). 

A  Torulacese  quite  similar  is  found  in  certain 
fermentations  of  tartrate  of  ammonia  and  of 
beer  yeast,  with  or  without  the  addition  of  car- 
bonate of  potash  (Pasteur). 

SECTION  (c):   MICROCOCCUS   PATHOGENES. 

Spherical  bacteria  found  in  affections  of  a  con- 
tagious nature. 


76  MORPHOLOGY  OF  THE  BACTERIA. 

M.  vaccinae,  Cohn  (Microsphcera  Vaccince,  Colin). 

Very  small  micrococci,  =  0.5/1  scarcely,  iso- 
lated or  united  in  pairs  in  recent  vaccine  virus 
and  in  the  pus  of  variola  pustules.  By  cultiva- 
tion, chaplets  of  from  two  to  eight  cells  may  be 
obtained,  then  masses  containing  sixteen  to 
thirty-two  cells  of  10  /x  and  more  diameter. 

The  M.  of  vaccine  virus  and  of  variola  are 
identical,  and  Cohn  regards  them  as  different 
races  of  the  same  species. 

M.  diphtheriticus,  Cohn. 

Granular  cells,  ovoid,  measuring  from  0.35  to 
to  1.1  ft,  isolated  or  more  often  united  in  twos 
or  in  a  chaplet  of  four  to  six  cells ;  sometimes 
multiplying  in  colonies  and  extending  them- 
selves in  all  the  diseased  tissues,  decomposing 
and  destroying  them  ((Ertel). 

M.  septicus,  Cohn  (Microsporon  septicus,  KlebsJ. 
Little  rounded  cells,  of  0.5  /x,  motionless  and 
crowded  in  masses  or  united  in  chaplets,  in  the 
secretion  of  wounds  in  cases  of  septicemia 
(Klebs),  in  zooglcea  in  callous  ulcers,  in  isolated 
cells,  united  in  pairs,  or  in  chaplets  in  the  se- 
rum of  epidemic  puerperal  fever  (Waldyer),  in 
all  the  tissues,  vessels,  etc.,  in  cases  of  pyemia 
and  septicemia. 

M.   bombycis,    Cohn  (Mycrozyma    bombycis,  Be- 
champ). 

Cells  with  a  diameter  of  1  ^  ordinarily  united 
in  chaplets  of  two,  three,  four,  five,  or  more,  in 


CLASSIFICATION  OF  THE  BACTERIA.  77 

the  intestine  of  silkworms  sick  with  "  la  flach- 
crie  "  (Pebrine). 

In  a  more  recent  work,  Colin  (Beitrage,  1875, 
p.  201)  gives  them  an  oval  form  and  a  diameter 
of  0.5  [M  at  the  outside. 

We  omit  in  the  present  edition  the  various  pathogenic 
Micrococci  described  by  Hallier,  and  introduce  in  place  of 
them  several  species  (?)  which  have  been  studied  by  more 
recent  authors,  and  which  seem  to  be  better  established. 

(G.  M.  S.) 

M.  of  erysipelas,  Fehleisen. 

Ver}'  minute  (smaller  than  the  micrococci  of  vaccinia) , 
found  in  zoogloea  masses  in  the  lymphatics  of  the  skin  at 
the  margin  of  the  zone  of  redness  in  extending  erysipela- 
tous  inflammation. 

M.  of  pneumonia  (?),  Friedlander. 

Large  oval  micrococci,  surrounded  by  a  transparent 
capsule,  1  n  in  length,  in  pairs,  short  chains  or  zooglcea 
masses,  in  the  sputum  of  croupous  pneumonia  during  the 
early  stages  of  the  disease. 

M.  of  induced  septicaemia  in  rabbits,  Sternberg. 

Oval  micrococci,  surrounded  by  a  transparent  aureole  of 
mucus  (  ?)  material,  about  1  fi  in  length,  and  found  solitarj', 
in  pairs,  and  in  short  chains,  in  the  blood  and  sub-cutane- 
ous oxlema  of  rabbits  killed  by  the  sub-cutaneous  injection 
of  normal  human  saliva. 

M.  of  fowl  cholera,  Pasteur. 

Micrococci,  0.5 /A  in  diameter,  mostl}'  in  pairs  (figure  8) 
in  the  blood  and  tissues  of  fowls  affected  with  fowl 
cholera. 


78        MORPHOLOGY  OF  THE  BACTERIA. 

M.  of  swine  plague    (rouget  ou  mal  rouge   des  pores) , 

Pasteur. 

Said  by  Pasteur  to  closely  resemble  the  microbe  of  fowl 
cholera,  but  to  be  smaller  and  less  easily  seen.  Klein 
ascribes  this  disease  to  a  bacillus. 

M.  of  gonorrhoea  (.?),  Neisser. 

Found  in  pairs  or  in  sarcina-like  groups  of  four  in  gon- 
orrhoeal  pus,  invading  the  pus  corpuscles,  and  the  epithelial 
cells  from  the  urethra. 

M.  of  infectious  osteomyelitis  (?). 

Found  by  Becker  in  pus  from  unopened  abscesses  in  five 
cases  of  acute  osteomyelitis.  Not  to  be  distinguished  by 
its  morphological  characters  from  the  micrococcus  found 
in  the  pus  of  acute  abscesses  generally. 

M.  of  progressive  necrosis  in  mice,  Koch. 

Micrococci  0.5  ^  in  diameter,  in  chains  and  zoogloea,  in 
necrotic  tissues  of  mice  injected  with  putrid  fluids. 


MONADS. 

Beside  the  Spherobacteria  are  placed  the  Mon- 
ads, not  the  organisms  described  under  this  name 
by  the  older  microscopists,  comprising  micro- 
phytes, spores,  and  infusorial  animals,  but  the 
Monas  as  understood  by  botanists  of  the  present 
day.  Thus  limited,  the  Monads  include  also,  be- 
sides some  microphytes  related  to  the  Sphero- 
bacteria, and  differing  from  them  by  their  greater 
dimensions,  some  organisms  of  doubtful  affinities. 


CLASSIFICATION  OF  THE  BACTERIA.  79 

As  in  the  case  of  the  Micrococd  it  is  very 
probable  that  the  Monads  are  only  the  spores,  or 
lower  forms  of  bacteria  higher  in  the  scale.  Cohn 
places  the  Monas  vinosa  of  Ehrenberg  with  the 
Clathrocystis  roseopersicina,  Cohn  (Bacterium  ru- 
bescens,  Ray-Lank.),  considering  it  a  spore  of  the 
latter. 

Monas  vinosa,  Ehrb. 

Cells  spherical,  oval,  regular,  of  2.5  yu,,  often  united 
in  pairs,  formed  of  a  pink  substance  with  granules  of 
a  deeper  color,  having  spontaneous  movements,  ffab., 
waters  containing  decomposing  vegetable  matters 
(Ehrb.  1838,  Ch.  Morren  1841,  Perty  1852,  Cohn 
1875). 

M.  Okenii,  Ehrb. 

Cells  cylindrical ;  average  length  7  to  15  p  (Cohn), 
10  fj,  (Ehrb.),  sometimes  from  60  to  80  p  (Warming), 
diameter  5  //, ;  of  a  beautiful  red  color,  having  a  rapid 
gyratory  movement,  with  a  cilium  at  the  posterior 
extremity  or  two  cilia  at  the  two  extremities.  Hob., 
stagnant  water  (Ehrb.  1836,  Eichwald,  Weiss,  Cohn, 
etc.). 

M.  Warmingii,  Cohn. 

Cell  cylindrical,  pink,  containing  at  its  two  rounded 
extremities  some  deep-red  granules;  length  15  to 
20  /z,  width  8  p ;  movement  uncertain,  having  a  vi- 
bratile  cilium.  Hab.,  brackish  water  on  the  coast 
of  Norway  (Warming). 

M.  gracilis,  Warming. 

Cells  straight,  cylindrical,  pink,  rounded  at  the 
two  extremities  ;  length  60  p,  thickness  2  //, ;  move- 
ment slow.  Hal.)  fresh  water. 


80       MORPHOLOGY  OF  THE  BACTERIA. 

Ehdbdomonas  rosea,  Cohn. 

Cells  pale  pink,  isolated,  fusiform  ;  eight  times  as 
long  as  broad,  having  a  length  of  20  to  30  //,,  and  a 
width  of  3.8  to  5  fi;  having  a  slow  oscillatory  move- 
ment, the  pink  substance  containing  numerous  gran- 
ules of  darker  color  and  vacuoles.  Hob.,  stagnant 
water. 

Ophidomonas  sanguined,  Ehrb. 

Cells  pale  pink,  spiral,  rigid,  movement  active  ; 
thickness  3  /LI,  length  of  one  turn  of  the  spiral,  9  to 
12  //,.  jETa6.,  brackenish  waters  of  Denmark  (Warm- 
ing)- 

Spiromonas  Cohnii,  Warming. 

Cells  spiral,  flattened;  1J  turn  of  spiral,  diam.  1.2 
to  3.5  /x,  width  1.2  to  4  /i.  Hob.,  coast  of  Denmark. 


2.  MICROBACTEKIA,  Cohn. 

Rod-bacteria,  cells  cylindrical,  short,  having  spon- 
taneous movement. 

A  single  genus,  —  Bacterium. 

g.  Bacterium,  Duj.  emend. 

Cells  cylindrical  or  elliptical,  free  or  united 
in  pairs  during  their  division,  rarely  in  fours, 
never  in  chains  (leptothrix  or  torula),  sometimes 
in  zooglcea  (differing  from  the  Z.  of  spherical  B. 
by  a  more  abundant  and  firmer  intercellular 
substance),  having  spontaneous  movements,  os- 
cillatory and  very  active,  especially  in  media 
rich  in  alimentary  material  and  in  presence  of 
oxygen. 


CLASSIFICATION  OF  THE  BACTERIA.  81 

We  might,  as  in  the  Spherobacteria,  divide 
the  rod-bacteria  into  three  groups:  1.  the  bac- 
teria of  putrefaction,  B.  termo,  B.  litieola,  and 
their  varieties  ;  2.  the  Bacteria  of  the  lactic  and 
acetic  fermentations,  etc. ;  3.  Chromogenes,  B. 
of  colored  milk  and  pus. 

B.  termo,  Ehrb.  1830,  Duj.  (Vibrio  lineola,  Ehrb. 
ex.  p.  1838;  Monas  termo,  Miiller). 

Cells  cylindrical,  slightly  swollen  in  the  middle, 
isolated,  sometimes  united  in  pairs,  two  to  five  times 
as  long  as  wide;  length  2  to  3  yu,  thickness  0.6  to 
1.8  /JL  :  movements  oscillatory. 

Appears  at  the  end  of  a  very  short  time  in 
all  infusions  of  animal  and  vegetable  substances ; 
multiplies  with  rapidity  in  numerous  zooglcea ; 
then  disappears  as  other  species,  to  which  it 
serves  as  nutriment,  are  developed.  According 
to  recent  observations,  this  bacterium  has  cilia 
(Dallinger,  Drysdale,  Warming).  Warming  has 
also  found  it  in  the  state  of  torula. 

B.  termo  is  the  veritable  agent,  the  first  cause, 
of  putrefaction,  it  is  the  true  ferment  saprogene 
(Cohn). 

M.  "Warming  has.  recently  described  two  allied  forms :  — 
B.  griseum,  c"ells  larger,  more  rounded ;  length  2.5  to  4  /x, 

thickness  1.8  to  2.5  ^.     In  infusions  of  fresh  and  salt  water. 
B.  littoreum,  cells  elliptical  or  elongated,  slightly  rounded ; 

length  2  to  Q  fj.,  thickness  1 .2  to  2.4  p.    Coasts  of  Denmark. 

B.  lineola,  Cohn  ( Vibrio  lineola,  Ehrb.  ex  p., 
Duj.,  Miiller,  V.  tremulans,  Ehrb.,  Bacterium 
triloculare,  Ehrb). 


82       MORPHOLOGY  OF  THE  BACTERIA. 

Cells  cylindrical,  straight,  rarely  a  little  twisted, 
larger  than  the  cells  of  B.  termo,  isolated  or  united 
in  pairs,  sometimes  in  fours,  never  more ;  length 
3.8  to  5.25  /z,  thickness  attains  1.25  //, ;  movements 
like  those  of  B.  termo,  but  a  little  more  active. 

Is  found  in  various  vegetable  and  animal  in- 
fusions of  fresh  or  salt  water,  often  takes  the 
form  of  zooglcea  containing  motionless  rods  in 
their  mucus  substance.  Warming  has  met  it 
in  the  form  of  chains  composed  of  eight  to  ten 
cells  (torula).  Its  protoplasm  is  dotted  with  re- 
fractive granules. 

It  is  not  known  whether  B.  lineola  constitutes 
a  specific  ferment  (Cohn). 

The  B.  fusiform,  Warming,  differs  from  the  preceding  by 
the  form  of  its  body,  which  is  attenuated  at  the  two  extrem- 
ities ;  length  2  to  5  /z,  width  0.5  to  0.8  p ;  plasma  not  punc- 
tated. 

Beside  these  species,  which  have  been  well 
studied,  may  be  placed  the  following,  which 
demand  new  investigations :  — 

B.  punctum,  Ehrb. 

Elongated  rods,  oval,  colorless,  having  slow 
movements,  oscillating,  often  united  in  pairs; 
length  5.2  /*,  thickness  1.7  /*,.  Diverse  infusions 
of  animal  substances. 

B.  catenula,  Duj. 

Body  filiform,  cylindrical,  often  united  in 
three,  four,  or  five ;  length  3  to  4  /*,  thickness 
0.4  to  0.5  p..  In  fetid  infusions,  in  typhoid  fe- 
ver (Coze  and  Feltz). 


CLASSIFICATION  OF  THE  BACTERIA.  83 

Vibrio  lactic,  Pasteur. 

"  Articles  almost  globular,  very  short,  a  little 
swollen  at  the  extremities ;  length  of  an  article, 
1.6  /i,  of  a  series,  50  /*,." 

This  vibrio  seems  to  resemble  B.  catenula  or 
B.  termo.  It  is  developed,  according  to  Pas- 
teur, in  sweetened  liquids,  where  it  causes  the 
formation  of  Jactic  acid  and  the  coagulation  of 
the  casein  of  milk.  According  to  other  re- 
searches, coagulation  of  casein  results  from  the 
influence  of  a  soluble  ferment  (zymase),  and  not 
from  an  organized  ferment. 

Acetic  ferment  (Mycoderma  aceti,  Pasteur,  Ulvina 
aceti,  Ktg.). 

"  Articles  short,  constricted,  two  to  three  times  as 
long  as  broad  ;  length  1.5  /*,  often  united  in  long 
chains,  forming  pellicles  on  the  surface  of  a  liquid." 

This  species  is  also  very  similar  to  the  pre- 
ceding. It  must  not  be  confounded  with  the 
Mycoderma  vini,  which  may  develop  in  the 
same  media,  but  which  is  a  fungus  of  the  group 
of  Saccharomycetes. 

The  acid  fermentation  of  beer  seems  to  be 
due  to  a  form  of  Bacterium  resembling  B.  termo 
(Cohn),  but  a  little  larger  than  the  type.  Cohn 
has  found  it  in  beer  undergoing  acid  fermenta- 
tion, beside  oval  saccharomyces,  elliptical  bac- 
teria, having  movement,  often  united  in  pairs, 
rarely  in  fours,  etc. 

Vibrio  tartaric  right  (Pasteur). 

Bacteria  similar  to  those  of  the  lactic  fermentation, 


PLATE   IV. 

From  "  Pasteur's  Studies  on  Fermentation."   MacmiUan  fr  Co.,  London,  1879. 

"  The  engraving  represents  the  different  dfseased  ferments,  together 
with  some  cells  of  alcoholic  yeast,  to  show  the  relative  size  of  these 
organisms." 

FIG.  1  represents  the  ferments  of  turned  beer,  as  it  is  called.  These 
are  filaments,  simple  or  articulated  into  chains  of  different  size,  and  having 
a  diameter  of  about  the  thousandth  part  of  a  millimetre  (about  Yroirir 
inch).  Under  a  very  high  power  they  are  seen  to  be  composed  of  many 
series  of  shorter  filaments,  immovable  in  their  articulations,  which  are 
scarcely  visible. 

In  No.  2  are  given  the  lactic  ferments  of  wort  and  beer.  These  are 
small,  fine,  and  contracted  in  their  middle.  They- are  generally  detached, 
but  sometimes  occur  in  chains  of  two  or  three.  Their  diameter  is  a  little 
greater  than  that  of  No.  1. 

In  No.  3  are  given  the  ferments  of  putrid  wort  or  beer.  These  are 
mobile  filaments,  whose  movements  are  more  or  less  rapid,  according  to 
the  temperature.  Their  diameter  varies,  but  is  for  the  most  part  greater 
than  that  of  the  filaments  of  Nos.  1  and  2.  They  generally  appear  at  the 
commencement  of  fermentation,  when  it  is  slow,  and  are  almost  invari- 
ably the  results  of  very  defective  working. 

In  No.  4  are  given  the  ferments  of  viscous  wort,  and  those  of  ropy 
beer,  which  the  French  call  Jilante.  They  form  chaplets  of  nearly  spher- 
ical grains.  These  ferments  rarely  occur  in  wort,  still  less  frequently  in 
beer. 

No.  5  represents  the  ferments  of  pungent,  sour  beer,  which  possesses  an 
acetic  odor.  These  ferments  occur  in  the  shape  of  chaplets,  and  consist 
of  the  mycoderma  aceti,  which  bears  a  close  resemblance  to  lactic  ferments 
(No.  2),  especially  in  the  early  stages  of  development.  Their  physiolog- 
ical functions  are  widely  different,  in  spite  of  this  similarity. 

The  ferments  given  in  No.  7  characterize  beer  of  a  peculiar  acidity, 
which  reminds  one  more  or  less  of  unripe,  acid  fruit,  with  an  odor  sui generis. 
These  ferments  occur  in  the  form  of  grains  which  resemble  little  spheri- 
cal points,  placed  two  together  or  forming  squares.  They  are  generally 
found  with  the  filaments  of  No.  1,  and  are  more  to  be  feared  than  the 
latter,  which  cause  no  very  great  deterioration  in  the  quality  of  beer, 
when  alone.  When  No.  7  is  present,  by  itself  or  with  No.  1,  the  beer  ac- 
quires a  sour  taste  and  smell  that  render  it  detestable.  We  have  met 
with  this  ferment  existing  in  beer  unaccompanied  by  other  ferments,  and 
have  been  convinced  of  its  fatal  effects. 

No.  6  represents  one  of  the  deposits  belonging  to  wort.  This  must 
not  be  confounded  with  the  deposits  of  diseased  ferments.  The  latter 
are  always  visibly  organized,  whilst  the  former  is  shapeless,  although  it 
would  not  always  be  easy  to  decide  between  the  two  characters,  if  sev- 
eral samples  of  both  descriptions  were  not  present.  This  shapeless  de- 
posit interferes  with  wort  during  its  cooling.  It  is  generally  absent 
from  beer,  because  it  remains  in  the  backs  or  on  the  coolers,  or  it  may 
get  entangled  in  the  yeast  during  fermentation,  and  disappear  with 
it.  Among  the  shapeless  granules  of  No.  6  may  be  discerned  little 
spheres  of  different  sizes  and  perfect  regularity.  These  are  balls  of 
resinous  and  coloring  matter  that  are  frequently  found  in  old  beer  at  the 
bottom  of  bottles  and  casks.  They  resemble  organized  products,  but 
are  nothing  of  the  kind. 


PLATE  IV 


CLASSIFICATION  OF   THE  BACTERIA.  85 

with  globular  articles,  short ;  diameter  1  yu,  united  in 
chains  of  50  jj,. 

Decomposes  racemic  acid,  causing  the  right 
tartaric  acid  to  disappear,  and  setting  free  left 
tartaric  acid. 

MlCROBACTERIA  CHROMOGENES. 

B.  xanthinum,  Schroeter  ( Vibrio  synxanihus,  Ehrb.). 

"  Bodies  cylindrical,  slightly  flexible,  formed  of  cor- 
puscles rarely  exceeding  five  in  number ;  length  of 
an  article,  0.7  to  1  p.  In  tainted  cow's  milk,  to  which 
it  gives  a  yellow  color." 

B.  syncyanum,  Schroeter  ( Vibrio  syncyanus,  Ehrb.). 
This  Bacterium,  which  has  the  same  charac- 
ters as  the  preceding,  has  been  observed  in  sour 
milk,  to  which  it  gives  a  blue  color. 

B.  ozruginosum,  Schroeter. 
In  greenish  blue  pus. 

These  B.  chromogenes  resemble  entirely  the 
lactic  vibrios,  B.  termo  or  catenula.  According 
to  Robin,  colored  milk  contains  colorless  vibrios, 
and  the  coloration  is  due  to  an  alga  similar  to 
Leptomitus. 

B.  brumieum,  Schroeter. 

Rods  in  a  brown  coloring  matter  in  infusions 
of  rotten  corn. 

Following  the  colored  Microbacteria,  I  place 
two  species  of  Bacterium  recently  described  by 
Ray-Lankester  and  Warming. 

B.  rubescens,  Ray-Lank.,  1873. 

Under  this   name    Ray-Lankester   has    described 


86        MORPHOLOGY  OF  THE  BACTERIA. 

some  phases  of  development  of  Clathrocystis  roseo- 
persicina  of  Cohn.  Now  Cohn  is  inclined  to  regard 
the  Monas  vinosa,  Ehrb.  as  the  wandering  cells  of 
Clathrocystis.  On  the  other  hand  Warming  has  de- 
scribed his :  — 

B.  sulfuratum,  Warming,  1876,  giving  it  for  synonymes, 
Monas  vinosa,  Ehrb.;  M.  erubescens,  Ehrb.;  M.  Warm- 
ingiii  Cohn;  Rhabdomonas  rosea,  Cohn.  It  follows, 
then,  that  the  Monas  which  we  have  described  with 
the  Spherobacteria  should  be  referred  to  a  Bacterium 
called  sulphuratum  by  Warming,  but  which  is  also 
identical  with  B.  rubescens  of  Ray-Lankester. 

3.  DESMOBACTERIA. 

Filiform  bacteria,  composed  of  elongated  cylin- 
drical articles,  isolated,  or  in  chains  more  or  less 
extended,  resulting  from  transverse  division.  Un- 
der this  form  they  correspond  to  leptothrix,  Auct. 
(differing  from  torula  in  that  the  filaments  are  not 
constricted  at  the  point  of  junction  of  the  articu- 
lations) ;  filaments  sometimes  united  in  swarms, 
never  in  zooglaa.  Movements  and  state  of  re- 
pose alternating  and  depending  upon  the  presence 
or  absence  of  oxygen,  the  reaction  of  the  medium, 
and  other  conditions  unknown.  Some  forms  never 
exhibit  movement. — Bacteridie  of  Davaine  (Cohn). 

We  will  only  preserve  in  the  Desmobacteria  the 
genus  Bacillus,  Cohn.  The  vibrios  are  rather  al- 
lied to  Spirillum  because  of  their  undulating  fila- 
ments. 

However,  after  the  exposition  of  the  different 
species  of  Bacillus,  we  will  say  something  of  three 
genera  of  colorless  oscillatoriacece,  which  are  nearly 


CLASSIFICATION   OF  THE  BACTERIA.  87 

related  to  them,  —  the  Leptothrix,  Beggiatoa,  and 
'Crenothrix. 

1.  Fil.  with  indistinct  articulations  : 

Fil.  very  slender,  short  ....  BACILLUS. 

Fil.  very  slender,  long   ....  LEPTOTHRIX. 

Fil.  thick,  broad BEGGIATOA. 

2.  Fil.  articulated  distinctly    ....  CRENOTHRIX. 

The  following  account  of  the  bacilli  has  been 
prepared  by  the  author  of  the  present  volume 
from  the  descriptions  given  by  Magnin  in  the  first 
edition,  in  connection  with  those  of  more  recent 
authors,  and  from  his  own  observations :  — 

g.  Bacillus,  Cohn. 

The  bacilli  are  short  rods,  which  may  be  joined 
in  leptothrix  chains,  or  may  grow  into  long  fila- 
ments, apparently  homogeneous,  but  in  which, 
by  the  use  of  staining  reagents,  the  protoplasm 
is  seen  to  be  divided  into  cubical  or  slightly 
elongated  masses.  Some  species  have  flagella 
and  are  motile  at  a  certain  period  of  their 
life-history ;  others  are  always  motionless.  They 
multiply  both  by  binary  division  and  by  the  for- 
mation of  highly  refractive  endogenous  spores, 
which  are  spherical  or  oval. 

B.  subtilis,  Cohn  (  Vibrio  suUilis,  Ehrb. ;   Ferment 
lutyrique,  Pasteur). 

This  is  the  common  "  hay-bacillus,"  a  widely 
distributed  species.  The  elementary  rods  are 


88        MORPHOLOGY  OF  THE  BACTERIA. 

from  2  to  6  /x  in  length,  and  about  2  //,  in 
thickness.  The  single  rods  and  short  chains 
exhibit  active  movements.  Upon  the  surface  of 
a  culture-medium  they  grow  into  long  motion- 
less leptothrix  filaments,  and  rapidly  develop 
spores.  These  are  oval,  highly  refractive  bodies, 
of  1  to  2  p  in  length,  and  from  .6  to  1  //,  in  thick- 
ness. (See  Plate  III.) 

B.  amylobacter,  Van  Tieghem  (Amylobacter,   Uro- 
cephalwn  and   Clostridium  Trecul). 

B.  occurring,  like  the  preceding,  under  various 
forms,  —  in  pointed  cylindrical  filaments  of  6.6  to 
26  jj,  in  length  and  1.1  /A  in  thickness,  or  in  form  of 
tadpole,  with  a  spore  in  the  terminal  swelling,  or  of  a 
spindle,  with  a  spore  in  the  middle.  In  fact,  it  does 
not  differ  from  B.  subtilis,  except  by  the  appearance 
of  starch  in  its  protoplasm  at  the  end  of  the  period 
of  multiplication.  These  B.  are  sometimes  endowed 
with  movement  (Ny lander). 

It  develops  in  vegetable  tissues,  which  fall 
into  putrefaction,  spontaneously,  according  to 
Trecul,  or  introduced  from  without  by  a  mech- 
anism still  unknown.  This  is  the  essential  agent 
of  vegetable  putrefaction  (Van  Tieghem). 

B.  ulna,  Cohn  (  Vibrio  bacillus,  Ehrb.). 

Filaments  articulated,  thick,  and  rigid,  formed  of 
one,  two  to  four  articles,  straight  or  broken  in  zigzag; 
length  of  an  article  10  /i,  length  of  a  filament  of  four 
articles  42  ^ ;  slow  movements  of  rotation  and  of 
progression. 


CLASSIFICATION  OF  THE  BACTERIA.  89 

B.  rnber,  Cohn. 

Long  rods,  isolated  or  united  in  two  or  four, 
movement  very  active  ;  in  a  red  mucous  sub- 
stance, vermilion,  developed  upon  grains  of  rice. 
Observed  by  Franck  and  Cohn.  • 

B.  anthracis,   Cohn. 

Found  in  the  blood,  and  especially  in  the 
capillary  blood-vessels,  of  animals  affected  with 
anthrax.  From  5  to  20  /x  in  length,  and  about 
1  p,  in  thickness,  straight  or  slightly  curved, 
truncated,  motionless ;  growing  in  culture-solu- 
tions into  long  filaments,  which  are  often  twisted 
into  bundles.  These  filaments  appear  to  be 
homogeneous,  but  by  the  use  of  staining  re- 
agents the  protoplasm  is  seen  to  be  divided  into 
cubical  masses  contained  in  a  hyaline  sheath. 
Oval  spores  are  developed  at  intervals  in  these 
filaments  when  they  have  free  access  to  oxygen. 
(See  Plate  VIII.) 

B.  tuberculosis,  Koch. 

Found  in  the  sputum  of  phthisical  patients, 
in  tubercle  nodules  wherever  found,  in  caseating 
scrofulous  glands,  in  bovine  tuberculosis,  etc. 
Extremely  slender,  somewhat  flexible  rods, 
having  a  length  of  one-quarter  to  one-half  the 
diameter  of  a  red  blood-corpuscle  (Koch),  mo- 
tionless, and  scarcely  discernible  except  when 
stained ;  often  containing  very  minute  spores. 
(See  Plate  IX.) 


90  MORPHOLOGY  OF  THE  BACTERIA. 

B.  leprae,  Hansen. 

Found  in  the  large  cells  of  leprous  nodules 
of  the  skin  and  of  internal  organs.  Extremely 
slender  rods,  which  in  form  and  staining  quali- 
ties are  said  greatly  to  resemble  the  bacilli  of 
tuberculosis ;  from  4  to  6  p.  in  length  and  having 
pointed  extremities.  Shining  oval  spores  have 
been  observed  in  the  rods,  and  they  are  said 
sometimes  to  be  motile.  (See  Fig.  16,  p.  332.) 

B.   of  symptomatic   anthrax   (Charbon    symptomat- 
ique ;  blackleg,  quarter-evil). 

Mobile  rods,  having  rounded  extremities, 
somewhat  shorter  and  broader  than  B.  anthracis. 
The  rods  sometimes  form  short  chains,  and  fre- 
quently contain  an  oval  spore  at  one  extremity. 
(See  Fig.  1,  Plate  VII.) 

B.   of  malignant   oedema,     Koch  ;    vibrion  septique, 
Pasteur. 

Rods  with  rounded  ends,  3  to  5/t  in  length 
and  I/A  in  thickness,  solitary  or  in  leptothrix 
chains;  forming  spores  without  free  access  of 
oxygen  —  anaerobic.  (See  Fig.  2,  Plate  VII.) 

B.  of  glanders,    Shiitz  and  Loffler. 

Extremely  minute  bacilli  found  in  the  nodules 
of  the  nasal  mucous  membrane,  and  of  internal 
organs  of  horses  dead  from  glanders. 


CLASSIFICATION  OF  THE  BACTERIA.  91 

B.  of  septicaemia  of  mice,  Koch. 

Extremely  minute  bacilli  .8  to  1  p,  long,  and 
.1  to  .2fM  thick,  solitary  or  in  short  chains;  found 
chiefly  in  the  white  blood-corpuscles  of  septicse- 
mic  mice.  (See  Fig.  19,  p.  353.) 

B.  of  cholera,  Koch. 

Found  in  the  rice-water  discharges  of  cholera 
patients,  and  within  the  mucous  membrane  and 
tubular  glands  of  those  dead  of  this  disease. 
The  bacilli  are  described  as  comma-shaped,  mo- 
bile organisms,  which  occur  in  wavy  masses,  and 
form  characteristic  colonies  in  gelatine  cultures. 

g.  Leptothrix,  Ktz. 

The  Leptothrix  differ  from  Bacilli  by  their  fila- 
ments being  very  long,  adherent,  very  slender,  and 
indistinctly  articulated.  Numerous  species  have  been 
described. 

g.  Beggiatoa,  Trev. 

Filaments  very  slender,  surrounded  by  mucous 
matter,  rigid,  having  oscillatory  movements.  Proto- 
plasm white,  enclosing  numerous  granules,  which 
recent  observations  have  demonstrated  to  be  crystal- 
line sulphur  (Cramer,  Cohn). 

4.  SPIROBACTERIA. 

This  tribe  includes  the  bacteria  with  undulating 
filaments,  or  filaments  in  spirals,  more  or  less  de- 


92        MORPHOLOGY  OF  THE  BACTERIA. 

veloped,  from  the  Vibrio  rugula,  which  only  pre- 
sents a  single  curve  in  its  centre,  to  certain  species 
of  Spirillum  which  have  numerous  turns  of  the 
spiral.  In  several  species,  cilia,  or  a  flagellum,  have 
recently  been  observed. 

We  divide  them  into  three  genera :  — 

Fil.  short,  slightly  sinuous    .     .     .   VIBRIO. 
Fil.  short,  spiral,  rigid     ....    SPIRILLUM. 
Fil.  long,  spiral,  flexible  ....    SPIROCHJETE. 

g.  Vibrio,  Auct.  emend. 

Body  filiform,  more  or  less  distinctly  articu- 
lated, always  undulating,  having  serpentine 
movements.  This  genus  forms  the  transition 
between  the  Desmobacteria and  Spirillum"hom 
which  it  cannot  be  separated  "  (Warming). 

Fil.  thick,  with  a  single  curve      ...   V.  RUGULA. 
Fil.  slender,  with  several  undulations    .    V.  SERPENS. 

V.  rugula,  Miiller  (V.  lineola,  Duj.  ex parte). 

Filament  presenting  in  its  centre  a  single  curva- 
ture, feeble  but  distinct ;  length  8  to  16  JJL.  The 
shortest  are  slightly  curved  (=6/1-  Warming),  the 
larger,  which  may  attain  17.6  /JL  (Cohn),  85  p  (Warm.), 
are  about  to  divide.  Movements  of  rotation  more  or 
less  rapid  around  their  longer  axis ;  of  progression 
forward,  giving  then  the  idea  of  a  serpentine  move- 
ment: having  a  cilium  (Warming). 

V.  rugula  is  commonly  found  in  swarms,  in 
infusions,  in  deposits  upon  the  teeth,  in  intes- 
tinal matters  (Leeuwenhoeck),  in  choleraic  dis- 
charges (Pouchet). 


CLASSIFICATION  OF  THE  BACTERIA.  93 

V.  serpens,  Miiller. 

Filament  one  half  less  in  diameter  than  the  pre- 
ceding, rigid,  annulate,  having  two  or  three  regular 
undulations,  at  least  two  m  the  shortest ;  height  of 
one  turn  of  the  undulations  8  to  12  yu,,  diameter  1  to 
3  /z,  total  length  11  to  25  /-t,  thickness  0.7  //, ;  move- 
ments analogous  to  those  of  B.  subtilis  ;  having  a  cil- 
ium  (Warm.). 

In  numerous  swarms  in  inf usions,  river  water, 
etc. 

g.  SpirochsBte,  Ehrb. 

S.  plicatilis,  Ehrb. 

Filament  not  extensible,  twisted  in  a  long  helix, 
flexible,  the  turns  of  the  spiral  near  together ;  suscep- 
tible of  twisting  upon  its  axis  and  of  an  undulatory 
movement ;  total  length  130  to  200  /z. 

Rare  species;  in  infusions,  stagnant  water, 
sea- water,  etc. 

S.  Obermeieri,  Cohn. 

Does  not  differ  from  the  preceding,  either  in  size, 
conformation,  or  in  its  movements,  but  by  its  habitat 
and  physiological  peculiarities. 

In  the  blood  of  persons  attacked  by  recurrent 
fever  (Obermeier,  1872,  Weigert,  Birch-Hirsch- 
feld,  etc.)  during  the  period  of  access,  never 
during  the  remission. 

S.  gigantea,  Wanning.  Found  upon  the  coasts  of  Den- 
mark ;  thickness  of  body,  3  p,  height  of  spiral  25  /i,  diam- 
eter 7  to  9  /*. 


94  MORPHOLOGY  OF  THE  BACTERIA. 

g.  Spirillum,  Ehrb. 

Filament  spiral,  rigid;  turns  of  spiral  short 
and  regular. 

S.  tenue,  Ehrb. 

Filament  slightly  tortuous,  three  to  four  turns  of 
the  spiral ;  length  and  diameter  of  a  single  turn,  2  to 
3  fi.  When  the  filament  has  a  turn  and  a  half,  it  re- 
sembles an  n, ;  the  filaments  of  two  to  five  turns  have 
a  length  of  4  to  15  /z, ;  spiral  movement  very  rapid. 

In  infusions,  etc. 

S.  undula,  Ehrb.  (Vibrio  prolifer,  Ehrb.) 

Filament  larger,  turns  of  the  spiral  wider  apart 
(from  3  to  5  /A)  ;  having  usually  one  half  a  turn  to 
one  full  turn,  rarely  one  and  a  half,  two,  or  three ; 
length  8  to  10  /*,  breadth  5  /i,  thickness  of  filament 
1.3  jj, ;  having  a  very  rapid  spiral  movement. 

Fetid  animal  and  vegetable  infusions  and  run- 
ning water. 

The  S.  rufum,  Pertz,  only  differs  from  this  by  its  reddish 
color. 

S.  volutans,  Ehrb. 

Filament  large  and  thick,  turns  of  spiral  regular, 
well  separated,  and  13  /z  in  height ;  number  of  turns 
two,  three,  and  three  and  a  half,  rarely  six  arjd  seven ; 
total  length  25  to  30  /*,  thickness  1.5  /x,  breadth  6.6  //,; 
movement  sometimes  rapid,  sometimes  motionless ; 
a  well-defined  cilium,  already  seen  by  Ehrenberg 
(Cohn,  Warming). 

This  giant  of  the  bacteria  is  found  in  vege- 
table and  animal  infusions,  in  sea-water,  and  in 
fresh  water. 


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PLATE  V. 

From  "  Microscopical  Journal." 

FIG.  1.  —  Micrococcus  prodigiosus  (Monas  prodigiosa,  Ehr.).  Spherical 
bacteria  of  the  red  pigment,  aggregated  in  pairs  and  in  fours  ;  the  other 
pigment  bacteria  are  not  distinguishable  with  the  microscope  from  this 
one. 

FIG.  2.  —  Micrococcus  vaccines.  Spherical  bacteria,  from  pock-lymph  in 
a  state  of  growth,  aggregated  in  short  four  to  eight-jointed  straight  or 
bent  chains,  and  forming  also  irregular  cell-masses. 

FIG.  3.  — Zoogloea-form  of  micrococcus,  pellicles  or  mucous  strata 
characterized  by  granule-like  closely  set  spherules. 

FIG.  4.  —  Rosary  chain  (Torula-form)  of  Micrococcus  urece,  from  the 
urine. 

FIG.  5.  —  Rosary-chain  and  yeast-like  cell-masses  from  the  white  de- 
posit of  a  solution  of  sugar  of  milk  which  had  become  sour. 

FIG.  6.  —  Saccharomyces  glutinis  (Cryptococcus  glutinis,  Fersen.),  a  pullu- 
lating yeast  which  forms  beautiful  rose-colored  patches  on  cooked 
potatoes. 

FIG.  7.  —  Sarcina  spec,*  from  the  blood  of  a  healthy  man,**  from  the 
surface  of  a  hen's  egg  grown  over  with  Micrococcus  luteus,  forming  yel 
low  patches. 

FIG.  8.  —  Bacterium  termo,  free  motile  form. 

FIG.  9.  —  Zoogloea-form  of  Bacterium  termo. 

FIG.  10.  —  Bacterium-pellicle,  formed  by  rod-shaped  bacteria  arranged 
one  against  the  other  in  a  linear  fashion,  from  the  surface  of  sour  beer. 

FIG.  11. —  Bacterium  lineola,  free  motile  form. 

FIG.  12. — Zooglcea-form  of  B.  lineola. 

FIG.  13.  —  Motile  filamentous  Bacteria,  with  a  spherical,  or  elliptical 
highly  refringent  "  head/'  perhaps  developed  from  gonidia. 

FIG.  14.  —  Bacillus  subtilis,  short  cylinders  and  longer,  very  flexible 
motile  filaments,  some  of  which  are  in  process  of  division. 

FIG.  15.  —  Bacillus  ulna,  single  segments  and  longer  threads,  some 
breaking  up  into  segments. 

FIG.  16. — Vibrio  rugula,  single  or  in  process  of  division. 

FIG.  17. — Vibrio  serpens,  longer  or  shorter  threads,  some  dividing  into 
bits,  at  *  two  threads  entwined. 

FIG.  18.  —  "  Swarm  "  of  V.  serpens,  th«  threads  felted. 

FIG.  19.  —  Spirillum  tenue,  single  and  felted  into  "  swarms." 

FIG.  20.  — Spirillum  undula. 

FIG.  21.  —  Spirillum  vofutans*  two  spirals  twisted  around  one  another. 

FIG.  22.  —  Spirochcete  plicatilis. 

All  the  figures  were  drawn  by  Dr.  Ferdinand  Cohn  with  the  immersion 
lens  No.  IX.  of  Hartnack  Ocular  III.,  representing  a  magnifying  power 
of  650  diameters. 


96        MORPHOLOGY  OF  THE  BACTERIA. 

M.  Warming  has  recently  described  three  new  species 
found  upon  the  coast  of  Denmark  :  — 

Sp.  violaceum,  height  8  to  10  /*,  diameter  1  to  1.5  /*,  thick- 
ness 3  to  4  p ;  a  cilium  at  each  extremity. 

Sp.  Rosenbergii,  height  of  helix  6  to  7.5  /i,  thickness  1.5  to 
2.6  p. 

Sp.  attenuatum,  body  very  attenuated  at  the  two  extrem- 
ities, without  a  cilium. 

We  give  below  some  details  concerning  the 
other  colorless  Schizophy tes :  — 

g.  Sarcina,  Goods. 

The  Sarcina,  which  it  is  useless  to  describe 
here,  can  be  considered  as  bacteria  in  which 
the  division  occurs  by  two  perpendicular  par- 
titions in  such  a  manner  that  multiplication 
takes  place  in  two  directions. 

Sarcina  is  very  nearly  allied  to  Merismopedia, 
from  which  it  only  differs  by  the  absence  of 
chlorophyll ;  its  siliceous  skeleton  allies  it  with 
the  diatoms. 

g.  Ascococcus,  Billr. 

Cells  hyaline,  small,  globular,  closely  united  in 
globular  or  oval  families,  irregularly  lobed  and  lobu- 
lated,  surrounded  by  a  thick  gelatinous  envelope, 
cartilaginous,  forming  a  soft  membrane,  flaky,  easily 
separating. 

A.  Billrothi,  Cohn. 

Families  in  masses  of  20  to  160  /i,  surrounded  by  a  thick 
membrane  of  15  /*. 

In  a  solution  of  tartaric  acid  exposed  to  the  air. 

g.  Myconostoc,  Cohn. 

Filaments  very  slender,  colorless,  folded,  rolled  up 
in  a  mucous  substance,  united  in  very  small  globules. 


CLASSIFICATION  OF  THE  BACTERIA.  97 

M.  gregarium^  Cohn. 

Unique  species  found  on  the  surface  of  a  putrefying 
infusion. 

g.  Cladothrix,  Cohn. 

Filaments  in  form  of  leptothrix,  very  slender,  color- 
less, not  articulated,  rigid  or  a  little  undulating,  falsely 
dichotomous. 

Cl.  dichotomy  Cohn.     In  foul  water, 
g.  Streptothriz,  Cohn. 

Filaments  in  form  of  leptothrix,  very  slender,  color- 
less, not  articulated,  straight  or  slightly  spiral,  a  little 
branched. 

Str.  Fcersteri,  Cohn. 

In  concretions  in  the  lachrymal  canal  of  man. 


PART   SECOND. 
PHYSIOLOGY   OF   THE   BACTEEIA. 


PAET   SECOND. 
PHYSIOLOGY   OF  THE    BACTERIA. 

CHAPTER  I. 

DEVELOPMENT  OF  THE  BACTERIA. 

THE  bacteria  are  now  known  to  us  from  a  mor- 
phological point  of  view :  let  us  proceed  to  study 
the  life  of  these  microscopic  beings ;  first,  from 
a  general  point  of  view,  that  is  to  say,  by  study- 
ing their  functions  of  nutrition  and  reproduction, 
independently  of  the  special  characters  impressed 
upon  these  functions  by  certain  media;  then  by 
considering  the  relations  which  are  established 
between  the  bacteria  and  the  particular  media  in 
which  they  may  be  developed. 

The  bacteria  are  of  all  beings  the  most  widely 
diffused.  We  meet  them  everywhere,  —  in  the 
air,  in  water,  upon  the  surface  of  solid  bodies,  in 
the  interior  of  plants  and  animals.  If  we  expose 
a  transparent  liquid  containing  traces  of  organic 
substances,  we  find  after  a  short  time  that  it  has 
become  clouded,  and  the  microscope  shows  us  that 
it  contains  myriads  of  these  beings. 

What  is  the  source  of  these  organisms  so  widely 
disseminated,  and  which  develop  so  rapidly?  This 


DEVELOPMENT  OF  THE  BACTERIA.      101 

is  the  first  question  which  presents  itself, — a  ques- 
tion which  has  given  rise  to  long  discussions,  in 
the  examination  of  which  we  shall  only  enter  in 
order  to  give  a  short  historical  statement. 

§  1.  —  ORIGIN  OF  THE  BACTERIA. 

The  origin  of  the  bacteria,  as  of  all  the  other 
inferior  organisms,  is  conceived  in  three  different 
manners :  — 

1.  For  some,  these  organisms  are  produced  by 
heterogenesis  ;  that  is  to  say,  by  creation  outright 
from  mineral  or  organic  substances  (spontaneous 
generation). 

2.  According  to  others,  they  come  directly  from 
individuals  like  themselves,  by  one  of  the  known 
modes  of  generation,  —  fission,  spores,  etc. 

3.  Finally  it  is  believed  that  they  are  derived 
from  organisms  already  existing,  and  are  nothing 
more  than  different  states  or  phases  of  develop- 
ment of  known  species,  of  which  the  life  cycle  is 
not 'yet  discovered. 

We  will  examine  the  latter  hypothesis,  which 
constitutes  what  is  called  polymorphism,  when  we 
speak  of  the  phenomena  of  reproduction. 

As  to  the  two  first,  we  will  content  ourselves 
with  indicating  the  late  works  which  have  appeared 
for  and  against  each;  insisting  above  all  upon  the 
facts  which  relate  to  the  proof  of  the  presence  of 
bacteria  or  their  germs  in  the  air,  water,  and 
liquids  or  tissues  of  the. human  organism,  —  blood, 
urine,  etc. 


102       PHYSIOLOGY  OF  THE  BACTERIA. 

Heter agenesis.  —  Since  the  experiments  of  Pou- 
chet  and  of  his  pupils,  and  the  arguments  given 
by  MM.  Trecul  and  Fremy,  the  last  facts  invoked 
in  favor  of  heterogenesis  are  due  to  MM.  Onimus, 
Servel,  Bastian,  etc. 

M.  Onimus  contends  that  the  "  proto-organisms 
may  be  born  in  media,  protected  against  the  air, 
which  contain  albuminoid  substances." 

M.  Martin  sustains  an  analogous  idea.  Accord- 
ing to  him,  the  bacteria  are  derived  from  protein 
granules.  According  to  Neusch,  bacteria  are  pro- 
duced in  the  interior  of  animal  or  vegetable  cells 
without  any  lesion  and  without  coming  from  the 
air.  To  demonstrate  this  he  plunges  divers  fruits 
under  water,  in  saline  or  acid  liquids  (phosphates, 
sulphates,  carbonate  of  potassa,  etc.),  and  he  finds 
there  bacteria ;  but,  according  to  him,  these  are 
not  living  organisms,  properly  so  called,  but  ab- 
normal cellular  vegetations. 

M.  Servel,  decapitating  some  guinea-pigs,  caused 
the  heads,  the  livers,  and  the  kidneys  to  fall  into 
a  solution  of  chromic  acid,  1  to  100.  At  the  end 
of  several  days,  the  superficial  parts  were  hard- 
ened ;  but  the  centre  was  softened,  and  filled  with 
bacteria. 

The  presence  of  bacteria  in  eggs  has  several 
times  been  verified,  and  the  heterogenists  have 
hastened  to  draw  an  argument  from  this  fact  in 
favor  of  their  theory.  M.  Gay  on  explains  the  ap- 
pearance of  these  organisms  in  the  eggs  of  birds 
by  their  presence  in  the  normal  state  in  the 
oviducts. 


DEVELOPMENT  OF  THE  BACTERIA.      103 

Finally,  Bastian,  having  succeeded  in  obtaining 
bacteria  in  liquids  which  he  believes  deprived  of 
every  germ,  believes  in  their  spontaneous  genera- 
tion. The  following  is  a  resume  of  his  experiment : 
Normal  acid  urine  is  brought  to  the  boiling- 
point,  then  a  solution  of  potash  (in  sufficient  quan- 
tity to  neutralize  the  volume  of  urine  employed) 
is  also  brought  to  the  boiling-point ;  after  cooling, 
the  two  liquids  are  mixed,  and  the  whole  placed 
in  an  oven  at  50°.  At  the  end  of  two  or  three 
days,  bacteria  are  developed. 

Pasteur  points  out  three  causes  of  error  in  the 
experiment  of  Bastian :  1.  The  germs  may  come 
from  the  urine ;  2.  The  germs  may  come  from  the 
solution  of  potash;  3.  The  germs  may  be  fur- 
nished by  the  vessels  employed  in  the  experiment. 
In  support  of  this  criticism,  Pasteur  has  made  some 
similar  experiments,  guarding  against  these  causes 
of  error,  and  has  not  obtained  bacteria. 


DISSEMINATION  OF  BACTERIA  IN  AIR  AND  WATER. 

Air.  —  The  experiment  of  Pasteur  for  gathering 
atmospheric  germs  is  well  known.  He  fixes  a 
glass  tube  in  an  aperture  made  in  a  window-blind. 
The  extremity  of  the  tube,  which  communicates 
with  the  open  air,  is  closed  with  a  plug  of  cotton, 
to  the  other  extremity  is  attached  an  aspirator. 
When  the  air  has  filtered  through  the  cotton  for 
some  hours,  this  is  examined,  and  is  found  to  be 
filled  with  germs. 


104  PHYSIOLOGY  OF  THE   BACTERIA. 

Before  Pasteur,  Ehrenberg  and  G.  de  Claubry 
had  already  announced  the  presence  in  the  air  of 
the  eggs  of  infusoria.  Robin  had  also  recognized 
that  the  atmosphere  contains,  in  addition  to  all 
sorts  of  debris,  spores,  pollen-grains,  portions  of 
insects,  and  rarely  the  eggs  of  infusoria.  More 
recently  Maddox  and  Cunningham,  by  the  aid  of 
an  aeroscope  invented  by  the  former,  gathered 
numerous  microbes,  as  well  as  bacteroid  particles. 
Tyndall,  by  causing  a  ray  of  light  to  enter  a  dark- 
ened chamber,  has  rendered  visible  all  these  mi- 
nute corpuscles.  His  researches  show  that  the 
optical  examination  of  air  enables  us  to  determine 
in  an  exact  manner  the  presence  or  absence  of 
germs. 

Let  us  also  mention  the  experiments  recently 
made  by  Miquel  in  the  park  of  Montsouris.  This 
observer  has  found  in  the  atmosphere  a  consider- 
able number  of  germs.  For  the  forms  of  which 
the  diameter  exceeds  2  p,  he  has  ascertained  that 
"  the  average  number  of  microbes  in  the  air  is 
feeble  in  winter  and  augments  rapidly  in  spring, 
etc. ;  2.  That  rain  always  diminishes  the  number 
of  these  microbes;  3.  That  rain-water  introduced 
with  the  greatest  precautions,  into  flasks  with  slen- 
der curved  necks,  first  heated  to  destroy  germs, 
rarely  contains  rotifers,  etc.,  but  always  contains 
bacteria." 

En  resumt,  the  existence  of  germs  can  be  dem- 
onstrated, 1,  by  direct  research  ;  and  2,  by  cultiva- 
tion. Direct  research  may  be  made  by  the  optical 
examination  of  the  air  (method  of  Tyndall),  the 


DEVELOPMENT  OF  THE  BACTERIA.      105 

microscopic  examination  of  dust  (method  followed 
by  Marie-Davy,  Tissandier),  the  examination  of 
particles  obtained  by  filtration,  by  gathering  germs 
•with  an  aeroscope,  by  condensation  of  atmospheric 
moisture  upon  refrigerating  vases.,  etc.  The  culti- 
vations consist  in  exposing  to  the  air  which  is  to 
be  examined  some  liquids  in  which  all  pre-existing 
germs  have  been  destroyed  (Pasteur,  Tyndall, 
etc.).  This  method  has  shown  that  liquids  exposed 
in  an  atmosphere  deprived  of  all  germs  does  not 
undergo  putrefaction,  but  this  occurs  as  soon  as 
the  access  of  air  not  deprived  of  germs  is  per- 
mitted (Tyndall). 

All  of  these  methods  give  concordant  results; 
deposits  containing  germs  of  various  kinds  are 
always  obtained.  But  this  objection  presents  itself 
to  the  mind :  Do  the  bacteria  obtained  by  cultiva- 
tion exist  in  the  atmosphere  ?  or  do  they  come 
from  germs  which  have  developed  rapidly  upon 
finding  a  favorable  medium  ?  From  the  experi- 
ments of  Cohn,  Miquel,  etc.,  it  is  known  that  the 
atmosphere  contains  very  few  adult  bacteria.  Mi- 
quel in  a  recent  communication  says,  in  effect,  that 
bacteria  are  rarely  found  in  the  air  in  a  complete 
state,  but  rather  under  the  form  of  shining  points, 
difficult  to  distinguish  directly  one  species  from 
another.  Are  not  these  brilliant  points  Micrococcif 
In  other  terms,  the  air  contains  permanent  spores, 
organisms  which,  as  we  shall  see  in  speaking  of  the 
reproduction  of  the  bacteria,  develop  at  a  certain 
period  of  the  existence  of  the  adult  forms,  in  their 
interior,  which  escape  from  the  sporogenous  fila- 


106  PHYSIOLOGY   OF  THE  BACTERIA. 

ment,  are  drawn  into  the  air  by  the  evaporation  of 
the  liquid  containing  them,  or,  after  dessication,  by 
the  winds.  These  spores  are  the  point  of  depart- 
ure of  epidemic  foci,  and  their  extreme  lightness 
explains  how  readily  they  are  disseminated  by  the 
winds. 

Water.  —  Water  contains  considerable  quantities 
of  bacteria  and  especially  of  germs.  Their  pres- 
ence in  atmospheric  water  is  established  by  the 
experiments  of  Lemaire  and  Gratiolet,  —  and  after 
them  by  more  recent  observers,  —  by  means  of  con- 
densers filled  with  ice,  and  placed  in  the  fields  and 
for  comparison  in  closed  apartments.  Rindfleisch 
has  since  expressed  the  opinion  that  the  vapor  of 
water  does  not  contain  spores  or  bacteria,  and  that 
telluric  waters  alone  contain  them ;  but  Billroth, 
Cohn,  and  others  have  proved  that  Kindfleisch  was 
too  positive  in  his  statement. 

It  is  not  surprising  that  telluric  waters  contain 
such  a  quantity  of  bacteria  that  their  existence  is 
admitted  by  all.  The  dust  gathered  upon  the  sur- 
face of  stones,  of  leaves,  of  fruits,  etc.,  shows  upon 
microscopic  examination  an  abundance  of  germs 
(Mari£-Davy,  Tissander) ;  the  washing  of  these 
objects  and  of  the  soil  by  the  rain  transports  them 
into  the  rivers  and  from  the  rivers  to  the  sea, 
which  contains  considerable  quantities  of  them. 

Thus,  a  drop  of  water  from  the  Seine,  according 
to  Pasteur  and  Joubert,  is  always  fecund,  and  may 
give  birth  to  several  species  of  bacteria.  The  dis- 
tilled water  of  laboratories  also  contains  germs,  and 


DEVELOPMENT  OF  THE  BACTERIA.      107 

these  of  so  small  a  diameter  that  they  pass  through 
all  filters.1  Cohn  has  proved  that  some  are  not 
arrested  by  a  super  position  of  sixteen  filters.  The 
only  waters  which  do  not  contain  them  are  those 
drawn  from  the  very  source  of  a  spring. 

DISSEMINATION  OF  BACTERIA  IN  THE  HUMAN 
ORGANISM. 

If  bacteria  are  so  generally  disseminated  in  the 
great  external  media,  it  is  not  surprising  that  they 
are  found  on  the  surface  of  the  human  body  and 
in  the  interior  of  the  organs  in  communication 
with  the  exterior.  But  to  account  for  their  pres- 
ence in  the  interior  of  organs  we  find  ourselves  in 
presence  of  two  hypotheses:  one  admitting  the 
spontaneous  production  of  these  organisms  in  the 
interior  of  the  tissues,  the  second  explaining  it 
by  the  introduction  through  the  membranes  of  the 
germs  of  bacteria  from  without. 

1  Having  been  directed  by  the  National  Board  of  Health  to  make 
some  experiments  with  a  view  to  confirming  or  disproving  the  results  of 
Klebs  and  Crudelli,  who  claim  to  have  found  the  germ  of  malarial  fevers 
in  the  atmosphere  of  the  Pontine  marshes  near  Rome  (their  Bacillus  ma- 
laria), I  aspirated  ten  gallons  of  air  on  the  edge  of  a  swamp  in  the  vicin- 
ity of  New  Orleans,  through  4  c.c.  of  distilled  water.  Upon  examining 
this  water  with  the  microscope  on  the  following  morning,  I  was  surprised 
to  find  a  large  number  of  actively  moving  bacteria  and  monads  (Monas 
lens).  To  make  sure  that  these  really  came  from  the  air,  I  examined  my 
distilled  water,  which  had  been  standing  in  the  laboratory  for  several 
weeks  (in  a  bottle,  corked,  but  occasionally  opened  as  distilled  water  was 
required)  and  found  the  s-ame  forms  present  in  considerable  numbers, 
not  so  numerous,  however,  as  in  the  water  through  which  swamp  air  had 
been  drawn.  As  the  germs  were  present  in  the  distilled  water,  I  presume 
that  the  passing  of  air  through  it  for  several  hours,  and  the  organic 
matter  contained  in  it,  favored  the  development  and  multiplication  of 
these  micro-organisms.  Subsequent  experiments  with  freshly  distilled 
water  gave  very  different  results  as  to  the  number  of  organisms  found 
—  G.  M.  S. 


108  PHYSIOLOGY  OF  THE  BACTERIA. 

In  truth,  the  cutaneous  surfaces  are  penetrated 
with  difficulty  by  germs,  although  the  hairs  upon 
the  surface  of  the  body  serve  to  collect  them. 
The  short  hairs  in  the  nares  prevent,  to  some  ex- 
tent, the  atmospheric  germs  from  penetrating  into 
the  bronchi,  but  this  protection  is  not  sufficient ; 
and,  notwithstanding  the  mucus  of  the  nasal  fossse 
and  of  the  pharynx,  they  may  be  found  in  the  al- 
veoli of  the  lungs,  if  we  may  believe  Rindfleisch 
and  Eberth.  Do  the  bacteria  pass  into  the  blood  ? 
They  may  be  transported  in  food  and  drink  into 
the  alimentary  canal,  where  an  elevated  tempera- 
ture, the  presence  of  saliva,  etc.,  favor  their  de- 
velopment. On  the  other  hand,  the  acid  secretions 
of  the  stomach,  the  bile,  and  the  pancreatic  juice 
moderate,  if  they  do  not  prevent,  the  multiplica- 
tion of  these  organisms. 

The  presence  of  bacteria  in  normal  blood  and 
urine,  or  their  occasional  entrance  into  these  fluids, 
are  important  questions,  which  have  induced  many 
contradictory  researches,  but  which  are  not  yet 
definitely  settled.1 


1  "  If  there  is  any  organism  in  the  blood  of  yellow  fever  demon- 
strable by  the  highest  powers  of  the  microscope  as  at  present  perfected, 
the  photo-micrographs  taken  in  Havana  should  show  it.  No  such  organ- 
ism is  shown  in  any  preparation  photographed  immediately  after  collection.  But 
in  certain  specimens  kept  under  observation  in  culture  cells,  hyphomy- 
cetous  fungi  and  spherical  bacteria  made  their  appearance  after  an  inter- 
val of  from  one  to  seven  days.  The  appearance  of  these  organisms  was, 
however,  exceptional ;  and  in  several  specimens  taken  from  the  same 
individual  at  the  same  time,  it  occurred  that  in  one  or  two  a  certain  fun- 
gus made  its  appearance,  and  in  others  it  did  not.  This  fact  shows  that 
the  method  employed  cannot  be  depended  upon  for  the  exclusion  of  atmos- 
pheric germs,  but  does  not  affect  the  value  of  the  result  in  the  consider- 
able number  of  instances  in  which  no  development  of  organisms  occurred 


DEVELOPMENT  OF  THE  BACTERIA.      109 

Two  kinds  of  researches  have  been  undertaken 
for  the  purpose  of  discovering  germs  in  normal 
blood.  The  direct  method,  or  microscopic  exam- 
inatfon,  has  given  results  very  much  disputed. 
The  blood  contains,  indeed,  a  considerable  number 
of  little  granules,  of  which  the  nature  is  doubtful, 
and  which  it  is  difficult  to  distinguish  from  Micro- 
coccus.  Thus,  while  Lu'ders  asserts  that  normal 
blood  contains  germs,  or  spores,  which  only  await 
a  favorable  alteration  in  the  fluid  in  order  to  de- 
velop themselves,  Rindfleisch  formally  denies  their 
existence. 

The  indirect  method,  which  consists  in  cultivat- 

in  culture  cells  in  which  blood,  in  a  moist  state  was  kept  under  daily 
observation  for  a  week  or  more. 

"  The  method  employed  seemed  the  only  one  practicable  for  obtaining 
blood  from  a  large  number  of  individuals  without  inflicting  unwarrant- 
able pain  and  disturbance  upon  the  sick.  It  was  as  follows :  One  of  the 
patient's  fingers  was  carefully  washed  with  a  wet  towel  (wet  sometimes 
with  alcohol  and  at  others  with  water),  ancl  a  puncture  was  made  just 
back  of  the  matrix  of  the  nail  with  a  small  triangular-pointed  trocar 
from  hypodermic  syringe  case.  As  quickly  as  possible  a  number  of  thin 
glass  covers  were  applied  to  the  drop  of  blood  which  flowed.  And  these 
were  then  inverted  over  shallow  cells  in  clean  glass  slips,  being  attached 
usually  by  a  circle  of  white  zinc  cement.  In  dry  preparations,  which 
are  most  suitable  for  photography,  the  small  drop  of  blood  was  spread 
upon  the  thin  glass  cover  by  means  of  the  end  of  a  glass  slip. 

u  The  thin  glass  covers  were  taken  from  a  bottle  of  alcohol,  and 
cleaned  immediately  before  using;  and  usually  the  glass  slips  were 
heated  shortly  before  applying  the  covers,  for  the  purpose  of  destroying 
any  atmospheric  germs  which  might  have  lodged  upon  them.  These 
precautions  were  not,  however,  sufficient  to  prevent  the  inoculation  of 
certain  specimens  by  germs  floating  in  the  atmosphere  (Penicillium  and 
micrococci) ;  and  in  nearly  every  specimen  the  presence  of  epithelial  cells, 
and  occasionally  a  fibre  of  cotton  or  linen,  gave  evidence  that  under  the 
circumstances  such  contamination  was  unavoidable.  It  is  therefore  be- 
lieved that  any  organism  developing  in  the  blood  of  yellow-fever,  or 
of  other  diseases  collected  by  the  method  described,  or  by  any  similar 
method,  can  have  no  great  significance,  unless  it  is  found  to  develop  as 
a  rule  (not  occasionally)  in  the  blood  of  patients  suffering  from  the  dia- 


110  PHYSIOLOGY  OF  THE  BACTERIA. 

ing  normal  blood  in  flasks  perfectly  closed,  has  also 
given  some  favorable  results,  such  as  those  of 
Hensen,  Tiegel,  Billroth,  and  Nedvedsky,  and 
some  unfavorable  results,  as  those  of  Lliders»and 
Pasteur.  According  to  Nedvedsky,  the  blood  "  con- 
tains germs  capable  of  undergoing  in  it,  under 
certain  circumstances,  an  ulterior  development : 
these  are  the  ffemococcos."  If  these  germs  do  not 
give  birth,  normally,  to  bacteria,  it  is  because  the 
blood  is  as  injurious  to  them  as  the  most  advanced 
stages  of  putrefaction  (Billroth).  If  this  hypoth- 
esis is  true,  it  explains  several  embarrassing  facts, 
such  as  the  existence  of  micrococci  in  the  pus  of 

ease  in  question,  and  is  proved  by  comparative  tests  not  to  develop  in 
the  blood  of  healthy  individuals,  obtained  at  the  same  time  and  by  the 
same  method. 

"  Tried  by  this  test,  it  must  be  admitted  that  certain  fungi  and  groups 
of  micrococci,  shown  in  photographs  taken  from  specimens  of  yellow- 
fever  blood  collected  at  the  military  hospital  and  preserved  in  culture 
cells,  cannot  reasonably  be  lupposed  to  be  peculiar  to  or  to  have  any 
causal  relation  to  this  disease."  —  Preliminary  Report  of  Havana  Commis- 
sion to  National  Board  of  Health. 

In  subsequent  observations  upon  the  blood  of  malarial  fever,  of 
syphilis,  and  of  leprosy,  I  have  sometimes  obtained  a  development  of 
micrococci  in  culture  cells  where  all  possible  precautions  as  to  the  exclu- 
sion of  atmospheric  germs  had  been  taken,  and  in  one  case  have  seen 
the  development  of  PeniciUium  in  another  of  Sarcina.  The  last  observa- 
tion is,  so  far  as  I  know  unique,  and  I  have  still  in  my  possession  the 
culture-slide  containing  numerous  masses  of  Sarcina,  presenting  the 
characteristic  arrangement  of  the  cells  in  fours.  This  slide  was  put  up 
at  the  bedside  of  a  patient  suffering  from  intermittent  fever  in  the  Char- 
ity Hospital,  New  Orleans.  Evtry  precaution  was  taken  to  exclude  at- 
mospheric germs.  The  patient's  finger  was  washed  with  absolute  alcohol 
just  before  making  the  puncture  from  which  the  little  drop  of  blood  \\as 
obtained.  The  question  as  to  whether  in  this  and  similar  cases  the 
germs  of  the  organism  which  develops  come  from  the  atmosphere  or 
pre-existed  in  the  blood  is  one  to  which  I  propose  to  give  special  atten- 
tion ;  and,  after  further  experiment,  I  shall  discuss  it  in  my  report  to  the 
National  Board  of  Health.  — G.  M.  S. 


DEVELOPMENT  OF  THE  BACTERIA.      Ill 

closed  abcesses,  in  cysts,  in  urine  drawn  from  the 
bladder,  etc. 

§  2.  —  NUTRITION  AND  RESPIRATION  OF  THE 
BACTERIA. 

The  bacteria,  being  organisms  composed  of  a 
cell  membrane  of  cellulose,  and  of  protoplasmic 
contents,  deprived  of  chlorophyll,  must  receive 
nutriment  and  respire  in  the  same  manner  as  all 
the  colorless  vegetables  and  all  the  inferior  animals 
deprived  of  special  apparatus,  —  that  is  to  say,  by 
end  osmotic  absorption. 

Although  the  media  in  which  the  bacteria  de- 
velop are  various,  yet,  from  the  point  of  view  of 
the  nutritive  function,  they  act  everywhere^  ac- 
cording to  the  same  laws.  No  matter  in  what 
medium  they  live,  they  must  have  water,  nitro- 
gen, carbon,  and  oxygen,  as  well  as  certain  min- 
eral salts  which  enter,  but  in  quantities  exceedingly 
minute,  into  the  chemical  constitution  of  all  organ- 
ized bodies. 

Water.  —  This  element  is  indispensable  to  the 
active  life  and  development  of  the  bacteria.  Dessi- 
cation  arrests  completely  the  movements  of  those 
which  are  mobile,  and  the  functions  of  all  the 
bacteria  in  general ;  but  it  does  not  kill  them, 
at  least  if  it  be  not  prolonged  beyond  a  certain 
time.  The  micrococci  of  different  kinds  of  virus 
are  examples  of  the  continued  vitality  of  these 
organisms  after  dessication  for  a  considerable  time. 


112  PHYSIOLOGY   OF  THE  BACTERIA. 

The  bacteria  present  in  this  respect  numerous  va- 
riations according  to  the  species  and  the  period  of 
development  which  they  have  attained.  In  the 
state  of  permanent  spores,  they  are  extremely  ten- 
acious of  vitality.  They  resist  for  a  long  time 
not  only  dessication,  but  a  considerable  elevation 
of  temperature. 

Among  the  bacteria,  some  are  developed  in  liq- 
uids, —  the  greater  number,  —  others  upon  damp 
surfaces.  The  former  can  live  in  fresh  water,  sea- 
water,  thermal  waters,  and  the  liquids  of  animal 
or  vegetable  organisms,  etc.  A  surprising  fact 
is,  that  the  composition,  so  different,  of  fresh  and 
sea  water  appears  to  have  no  influence  upon  the 
bacteria.  We  find  in  both  all  the  species,  from 
Bacterium  termo  to  Spirillum  volutans. 

Nitrogen.  —  Pasteur  has  demonstrated  that  it  is 
not  necessary  that  the  nitrogen  which  is  to  serve  as 
nutriment  to  the  bacteria  should  be  in  the  form  of 
albumen,  but  that  these  organisms  can  take  posses- 
sion of  it  in  the  form  of  ammonia. 

In  fact,  in  Pasteur's  solution,  composed  as  fol- 
lows :  — 

Distilled  water 100. 

Sugar  candy 10. 

Tartrate  of  ammonia    ....  1. 

Ashes  of  one  gramme  of  yeast    .  0.075. 

the  bacteria  increase  sometimes  with  such  rapidity 
that  they  interfere  with  the  development  of  the 
alcoholic  ferment. 


DEVELOPMENT  OF  THE  BACTERIA.      113 

Cohn.  in  order  to  better  observe  the  phenomena 
and  to  get  rid  of  the  moulds,  which  the  cane-sugar 
caused  to  develop  too  rapidly,  employed  the  fol- 
lowing culture-fluid :  — 

Distilled  water  ....  100. 
Tartrate  of  ammonia  .  .  1. 
Ashes  of  yeast  ....  1. 

Bacteria  develop  in  this  fluid  wonderfully,  which 
proves  that  sugar  is  not  indispensable  to  them. 

One  other  solution  often  employed  is  that  of 
Mayer.  It  has  the  advantage  of  not  requiring  the 
employment  of  ashes  of  yeast :  — 

Phosphate  of  potash    ...  0.1  gramme. 

Sulphate  of  magnesia  ...  0.1       „ 

Tribasic  phosphate  of  lime   .  0.1       „ 

Distilled  water 20  c.c. 

Cohn  adds  to  this  0.2  gr.  tartrate  of  ammonia. 

En  resume,  the  bacteria  can  take  nitrogen,  which 
they  need  in  order  to  form  their  protoplasm,  either 
from  albuminous  compounds,  which  they  decom- 
pose, as  in  putrefaction,  or  in  the  form  of  am- 
monia, or,  perhaps,  by  borrowing  it  from  nitric 
acid,  but  this  last  source  is  not  well  established 
(Conn), 

Carbon.  —  In  addition  to  the  sources  common 
to  other  organisms,  the  bacteria  can  take  this  im- 
portant element  of  their  composition,  under  cer- 
tain circumstances,  from  the  organic  acids.  Thus, 
when  we  cultivate  bacteria  in  a  solution  containing 

8 


114  PHYSIOLOGY  OF  THE  BACTERIA. 

only  tartrate  of  ammonia  with  a  small  quantity  of 
mineral  salts  (phosphoric  acid,  potash,  sulphuric 
acid,  lime,  and  magnesia),  they  develop  rapidly, 
taking  their  carbon  from  the  tartaric  acid. 

Cohn  has  endeavored  to  ascertain  if  other  or- 
ganic acids  could  be  assimilated  by  the  bacteria. 
By  making  use  of  succinate  of  ammonia,  or  neutral 
acetate  of  ammonia,  he  has  been  able  to  cultivate 
these  microphytes.  Besides,  as  Pasteur  had  already 
experimented  with  solutions  containing  laotates,  and 
in  which  bacteria  had  developed  until  the  salt  had 
completely  disappeared,  we  may  admit  that  the 
bacteria  can  assimilate  the  organic  acids,  —  tartaric, 
succinic,  acetic,  and  lactic ;  but  tartaric  acid  seems 
to  furnish  the  best  alimentary  solution. 

Other  substances  containing  carbon  are  also  as- 
similated by  the  bacteria, — cane-sugar,  milk-sugar, 
glycerine,  and  even  cellulose  (according  to  Mit- 
scherlich). 

Cohn  concludes, "  that  the  bacteria  multiply  quite 
normally,  and  in  great  quantity,  whenever  they 
find  the  elements  in  solution  which  constitute 
ashes,  and  that  they  can  take  the  carbon  which 
they  need  from  any  organic  substance  containing 
it,  and  their  nitrogen  from  ammonia,  urea,  and 
probably  from  nitric  acid.  The  bacteria,  then,  re- 
semble green  plants,  in  that  they  assimilate  nitro- 
gen contained  in  their  cells  by  taking  it  from 
ammonia  compounds,  which  animals  cannot  do. 
They  differ  from  green  plants  in  that  they  cannot 
draw  their  carbon  from  carbonic  acid,  and  only 
assimilate  organic  substances  containing  carbon, 


DEVELOPMENT  OF  THE  BACTERIA.      115 

above  all  the  hydrates  of  carbon  and  their  deriv- 
atives ;  and  in  this  respect  they  resemble  animals." 

Absorption.  —  How  are  these  various  substances 
absorbed  ?  The  observations  of  Grimm,  Hoffmann, 
de  Seynes,  etc.,  permit  us  to  assure  ourselves  that 
these  organisms  absorb  by  endosmosis  the  sub- 
stances upon  which  they  are  nourished. 

Grimm,  upon  examining  with  the  microscope 
some  particles  of  lemon  containing  bacteria  and 
spores  of  algae,  saw  a  certain  number  of  the  former 
gather  around  a  spore,  and  fix  themselves  to  it 
by  one  of  their  extremities.  They  did  not  pene- 
trate it;  but  when  they  abandoned  it,  the  spore 
had  diminished  in  volume,  and  lost  a  portion  of  its 
contents,  while  the  bacteria  had  taken  a  greenish 
color. 

Hoffmann  has  seen  that  these  little  organisms, 
when  placed  in  a  solution  of  carmine  or  of  fu- 
schine,  after  a  time  are  colored  an  intense  red, 
while  the  mucus  surrounding  them  remains  color- 
less. 

De  Seynes,  also,  from  his  observations  upon 
the  vibrios  which  accompanied  some  colored  fila- 
ments of  Penicillium  glaucitm,  believes  that  bacte- 
ria are  susceptible  of  absorbing  coloring  matters 
from  vegetables  and  from  animals  with  which  they 
are  in  contact. 

Oxygen.  —  The  role  of  oxygen  in  the  life  of  the 
bacteria  has  given  rise  to  numerous  controversies. 
First,  it  seems  a  priori  that  the  bacteria  ought 


116  PHYSIOLOGY  OF  THE  BACTERIA. 

to  act  like  all  other  living  beings,  and  to  respire 
like  the  other  inferior  organisms  deprived  of  chlo- 
rophyll —  that  is  to  say  by  absorbing  oxygen  and 
eliminating  carbonic  acid.  This  is,  indeed,  the 
opinion  of  a  great  number  of  botanists.  But, 
according  to  Pasteur,  it  is  not  so  with  the  bacteria. 
When  we  examine  what  occurs  in  putrefaction, 
we  find  that  at  first  certain  species  are  developed 
(Monas  crepusculum,  Bacterium  termo,  etc.),  which 
absorb  all  the  oxygen  dissolved  in  the  liquid,  and 
come  to  the  surface  where  they  form  a  thick  veil ; 
after  this,  other  species  of  vibrioniens  appear, 
which  are  developed  in  a  medium  entirely  de- 
prived of  free  oxygen,  by  borrowing  this  gas 
from  the  fermentable  matters  contained  in  the 
liquid.  These  chemical  decompositions  constitute 
putrefaction. 

The  first  of  these  organisms,  regarding  the  na- 
ture of  which  Pasteur  has  long  been  uncertain, 
are  aerobies :  they  live  in  contact  with  the  air,  and 
have  need  of  oxygen.  The  second,  anaerobies, 
not  only  have  no  need  of  oxygen,  but  are  killed 
by  it. 

These  differences  in  the  respiration  of  organ- 
isms belonging  to  the  same  group  are  not  admitted 
by  a  great  number  of  recent  observers.  Hoff- 
mann, among  others,  says  expressly :  "  These  little 
beings  cannot  live  without  air,  I  should  say  with- 
out oxygen :  if  this  gas  is  wanting,  they  cease  to 
move  and  do  not  multiply  at  all.  If  a  drop  of 
liquid  full  of  bacteria  is  placed  upon  a  glass  slip, 
then  covered  by  a  piece  of  thin  glass,  the  active 


DEVELOPMENT  OF  THE  BACTERIA.      117 

bacteria  will  all  approach  gradually  to  the  margins 
of  the  cover;  and  it  is  there  that  at  the  end  of 
several  days,  after  the  successive  death  of  the 
greater  number,  some  are  still  found  endowed  with 
life  and  movement.  If  a  similar  preparation  is  at 
the  same  time  protected  by  an  impermeable  ce- 
ment against  dessication  and  against  the  introduc- 
tion of  atmospheric  air,  all  movement  among  the 
bacteria  will  cease  at  the  end  of  two  minutes,  pro- 
vided, however,  that  no  air  bubble  has  been  im- 
prisoned with  the  liquid." 

The  influence  of  oxygen  upon  the  life  and  de- 
velopment of  bacteria  is  also  very  manifest  in  an 
experiment  recently  made,  and  not  yet  published, 
by  Toussaint,  who  has  been  kind  enough  to  com- 
municate it  to  me. 

In  studying  the  development  of  the  spores 
of  Bacillus  anthracis  in  the  moist  chamber  of 
Ranvier,  Toussaint  has  observed  the  following 
curious  facts,  which  offer  a  striking  analogy  to 
those  above  mentioned,  borrowed  from  Hoff- 
mann. "  The  bacteria,  which  occupy  the  cen- 
tral portion  of  the  moist  chamber  and  which 
by  reason  of  their  situation  receive  very  little 
oxygen  from  the  groove,  are  soon  arrested  in 
their  development ;  while  those  which  occupy  the 
borders  are  long  and  heaped  up  in  immense  num- 
bers, those  in  the  centre  remain  small,  formed  of 
two,  four,  or  five  articles,  which  are  easily  sepa- 
rated from  each  other;  they  soon  cease  to  grow 
and  are  not  transformed  into  spores." 

Cohn  is  also  as  explicit.    "  There  is  no  doubt," 


118  PHYSIOLOGY  OF  THE  BACTERIA. 

he  says,  "  that  the  complete  development  of  Bacil- 
lus, and  above  all  reproduction  by  means  of  spores, 
is  only  made  under  the  influence  of  free  access 
of  air." 

We  might  explain  the  contradictory  facts  of 
Pasteur  by  admitting,  with  Cohn,  that  the  appear- 
ance of  different  roles  played  by  the  aerobics 
(Bacterium)  and  the  anaerobies  (Bacillus)  is  sim- 
ply due  to  a  veritable  struggle  for  existence  which 
takes  place  between  the  microbacteria  and  the 
desmobacteria. 

ACTION  OF  VAKTOUS  AGENTS  UPON  THE  BACTERIA. 

In  this  paragraph  I  shall  pass  in  review  the 
action  of  temperature,  of  movement,  and  of  va- 
rious antiseptics. 

Temperature.  —  It  is  very  important  to  study 
the  manner  in  which  bacteria  comport  themselves 
under  extreme  variations  of  temperature.  It  is, 
indeed,  upon  the  results  furnished  by  these  re- 
searches that  a  great  part  of  the  arguments  op- 
posed to  the  panspermatists  by  the  heterogenists 
are  based. 

We  shall  consider  the  influence  upon  bacteria 
of  moderate  temperatures  and  of  extremes  above 
and  below  zero. 

Moderate  temperatures  —  that  is  to  say  those 
which  are  comprised  between  25  and  40°  (77  to 
104°  Fah.)  —  are  generally  favorable.  The  most 
favorable  has  been  found  to  be  35°  (95°  Fah.) 
(Onimus). 


DEVELOPMENT  OF  THE  BACTERIA.      119 

The  degree  of  resistance  to  extreme  tempera- 
tures is  very  variable,  according  to  the  species. 
Thus,  according  to  Frisch,  a  temperature  of  45  to 
50°  (113  to  122°  Fah.)  is  sufficient  to  kill  B.  termo, 
whilst  80°  (176°  Fah.)  does  not  kill  the  "  Bacteri- 
dies  "  (Bacillus). 

The  permanent  spores  are  especially  remarkable 
by  the  tolerance  which  they  possess  for  high  tem- 
peratures. They  have  been  subjected  to  100° 
(212°  Fah.)  (Schwann),  110°  (Pasteur)  and  even 
130°  (Schrader)  without  losing  their  power  of 
germinating. 

We  must,  however,  recognize  that  the  results 
of  the  experimenters  offer  the  greatest  diversity, 
the  result,  according  to  Cohn,  of  the  difficulty  of 
obtaining  an  equable  distribution  of  the  heat  in 
the  media,  which  are  generally  bad  conductors. 

Cohn  has  arrived  at  the  following  conclusions  as 
the  result  of  numerous  experiments  made  upon 
the  Bacillus  of  hay  infusions  :  — 

1.  At  a  temperature  of  45  to  50°  (113  to  122° 
Fah.)   the   Bacillus   still    multiplies   rapidly,   and 
forms  as  usual  membranes  and  spores,  while  the 
other    schizophytes    existing    in    the    infusion    of 
hay  are  at  this  temperature  incapable  of   multi- 
plication. 

2.  At  a  temperature  of  50  to  55°  (122  to  131° 
Fah.)  all  reproduction  and  development  of  Bacillus 
ceases.     It  neither  forms  pellicles  or  spores;  the 
filaments  are  killed,  the  spores,  on  the  contrary, 
preserve,  for  a  longer  time  (for  at  least  seventeen 
hours)  the  property  of  germinating. 


120  PHYSIOLOGY  OF  THE  BACTERIA. 

3.  While  infusions  of  hay  are  generally  sterilized 
by  a  temperature  of  60°  (140°  Fah.)  or  more,  pro- 
longed during  twenty-four  hours,  certain  spores  of 
Bacillus  seem  able  to  endure  a  temperature  of  70 
to  80°  (158  to  176°  Fah.)  during  three  or  four 
days  without  losing  the  power  of  germinating. 

By  some  experiments  made  with  refrigerating 
mixtures,  Cohn  has  ascertained  that  the  bacteria 
are  not  killed  by  very  low  temperatures,  acting 
even  during  several  hours, —  18°  for  example 
(0°  Fah.).  But  they  are  benumbed  at  a  tempera- 
ture of  0°  (32°  Fah.)  and  probably  at  a  temperature 
a  little  higher,  losing  the  power  of  movement  and 
of  reproduction,  and  consequently  their  action  as 
ferments.  They  preserve,  however,  their  capacity 
to  resume  their  activity  at  a  more  elevated  tem- 
perature. 

Frisch  has  pushed  the  experiment  still  further 
than  Cohn.  By  the  evaporation  of  carbonic  acid, 
he  has  produced  as  low  a  temperature  as  —  87 J 
( —  123°  Fah.)  in  liquids  containing  bacteria,  with- 
out destroying,  the  vitality  of  these  organisms, 
development  having  subsequently  occurred  of  coc- 
cos  and  of  bacteria.  Congelation,  then,  cannot 
serve  to  destroy  the  organized  ferments. 

Let  us  add,  however,  that  if  the  passage  to  ex- 
treme temperatures  is  too  sudden,  there  is  then  an 
alteration  (destruction  ?)  of  these  organisms  (Schu- 
macher). 

Movement.  —  We  would  not  have  consecrated 
a  paragraph  to  the  action  of  movement  upon 


DEVELOPMENT  OF  THE  BACTERIA.      121 

bacteria,  if  Crova  had  not  recently  asserted  that 
movements  impressed  upon  a  liquid  containing 
bacteria  completely  arrests  their  development. 
This  is  an  assertion  in  complete  opposition  to  all 
that  we  know  of  the  physiology  of  these  organ- 
isms, and  which  it  is  difficult  to  reconcile  with  the 
fact  that  bacteria  may  develop  even  in  the  torrent 
of  the  circulation. 

Compressed  Air.  —  We  have  just  seen  the  in- 
fluence of  air,  and  especially  of  oxygen,  upon  the 
bacteria.  When  this  agent  is  in  a  certain  state  of 
tension,  it  acts  in  a  different  manner.  M.  Paul 
Bert  has  proved  that  under  a  tension  of  twenty- 
three  to  twenty-four  atmospheres  all  the  putrefac- 
tive processes  depending  upon  the  development  of 
vibrios  cease  to  occur.  Since,  the  same  savant 
has  found  that  the  anatomical  elements  and  even 
the  red  blood  globules  are  killed  by  oxygen. 
These  researches  agree  well  enough  with  those  of 
Grossmann  and  Mayerhauser  upon  the  life  of 
bacteria  in  gas.  From  their  numerous  experi- 
ments it  appears  that,  under  the  influence  of  oxy- 
gen, there  is  an  exaggeration  of  the  activity  of 
the  bacteria;  but  if  the  oxygen  is  under  a  pres- 
sure of  five  to  seven  atmospheres,  the  bacteria  live 
from  six  to  twenty  hours,  then  die,  and  cannot  be 
resuscitated  by  atmospheric  air. 

Ozone  causes  a  definite  and  almost  instantaneous 
arrest  of  movement. 


122  PHYSIOLOGY  OF  THE  BACTERIA. 

Other  gases  studied  by  the  same  savants  have 
given  the  following  results :  — 

Hydrogen  at  first  causes  an  acceleration  of 
movement,  which  is  maintained  for  several  days ; 
then  movement  becomes  less  active,  and  finally  it 
ceases  altogether. 

Carbonic  Acid.  —  Contrary  to  the  facts  stated 
by  Pasteur,  this  agent  was  found  to  paralyze  the 
bacteria,  and  reduced  them  to  complete  immobility. 
If  the  carbonic  acid  is  displaced  by  oxygen,  the 
bacteria  resume  their  activity. 

Chloroform.  —  This  substance,  according  to  the 
researches  of  Miintz,  arrests  the  vital  phenomena 
of  organized  ferments.  Miintz  uses  this  charac- 
ter in  order  to  recognize  the  soluble  ferments,  upon 
which  it  has  no  action. 

Boracic  Acid.  —  Since  the  labors  of  Dumas, 
which  have  demonstrated  that  boracic  acid  kills 
the  inferior  organisms  by  depriving  them  of  their 
oxygen,  this  substance  has  been  employed  in  vari- 
ous circumstances  as  an  antiseptic. 

Sulphate  of  Quinine.  —  The  action  of  quinine, 
either  in  the  state  of  chlorhydrate  or  of  sulphate, 
is  not  yet  well  established.  The  experiments  of 
Binz,  Manassein,  Kroevitsch,  Bochefontaine,  etc., 
have,  in  truth,  given  contradictory  results. 

Carbolic  Acid.  —  The  experiments  of  Manas- 
sein have  demonstrated  that  ^th  per  cent  of  car- 


DEVELOPMENT  OF  THE  BACTERIA,      123 

bolic  acid  is  sufficient  to  prevent  all  development 
of  living  beings.  It  is  employed  with  success  in 
anthrax,  in  the  treatment  of  wounds,  etc. 


§  3.  —  REPRODUCTION  OF  THE  BACTERIA. 

It  is  well  established  that  the  bacteria  can  mul- 
tiply by  fission,  and  reproduce  themselves  also  by 
the  formation  of  endogenous  spores. 

fission.  —  The  multiplication  by  fission  consists 
in  a  transverse  division  of  the  cell.  When  a  bac- 
terium has  attained  nearly  double  its  ordinary 
length,  we  see,  in  the  larger  species,  that  the  proto- 
plasm becomes  clearer  in  the  central  portion,  and  a 
partition  forms  in  the  median  line  separating  the 
contained  protoplasm  into  two  portions.  The  par- 
tition, at  first  very  delicate,  becomes  thicker,  di- 
vides into  two,  and  the  two  articles  separate. 

This  phenomenon  is  produced  more  or  less 
quickly  according  to  the  nature  of  the  medium, 
its  richness  in  nutritive  material,  the  temperature, 
etc.  When  the  growth  is  rapid,  the  new  cells  form 
more  quickly  than  they  separate,  and  are  arranged 
in  chaplets.  Very  often  we  only  find  them  in 
this  form,  in  strings  of  two  to  four  cells  coupled 
together.  In  some  forms  the  transverse  division 
is  preceded  by  constriction  near  the  middle  of  the 
cell.  Before  the  two  new  cells  are  separated,  the 
bacterium  in  this  case  presents  the  appearance  of 
a  figure  8,  and  seems  to  be  a  simple  cell  swollen 
at  the  two  extremities. 


124  PHYSIOLOGY  OF  THE  BACTERIA. 

Under  other  circumstances,  and  probably  in  con- 
sequence  of  a  mucus  transformation  of  the  walls 
of  the  mother  cells,  the  new  bacteria  are  envel- 
oped by  a  mass  of  glutinous  substance.  We  have 
described  these  masses  under  the  name  of  Zo- 
oglcea. 

The  conditions  which  favor  multiplication  by 
fission  are,  a  certain  degree  of  temperature  and 
a  sufficient  quantity  of  nutritive  material.  The 
higher  the  temperature,  the  more  rapid  is  the 
segmentation  of  the  bacteria,  the  more  rapid  their 
multiplication,  —  that  is  to  say,  up  to  a  certain 
limit,  variable  with  the  species  and  beyond  which 
the  bacteria  are  destroyed. 

The  multiplication  decreases  when  the  tempera- 
ture is  lower,  and  ceases  entirely  in  the  vicinity 
of  0°  (32°  Fah.). 

The  influence  of  richness  of  nutriment  is  well 
seen  in  artificial  cultivation.  So  long  as  the  bacte- 
ria find  the  necessary  aliment,  in  sufficient  quantity, 
to  form  new  protoplasm,  they  multiply  with  ac- 
tivity ;  but  as  soon  as  the  organic  matter  is  de- 
voured, they  cease  to  divide,  fall  to  the  bottom 
of  the  vessel,  where  they  accumulate,  motionless, 
and  form  a  deposit  more  or  less  abundant. 

The  multiplication  of  the  bacteria  by  binary  fis- 
sion has  for  result,  if  nothing  occurs  to  interfere 
with  the  most  favorable  conditions,  the  invasion 
of  the  medium  by  an  incredible  number  of  these 
little  beings,  of  which  we  can  only  form  an  idea 
by  calculation. 

"  Let  us  suppose,"  says  Cohn,  "  that  a  bacterium 


DEVELOPMENT  OF  THE  BACTERIA.      125 

divides  into  two  in  the  space  of  an  hour,  then  in 
four  at  the  end  of  a  second  hour,  then  in  eight 
at  the  end  of  three  hours,  in  twenty-four  hours 
the  number  will  already  amount  to  more  than  six- 
teen millions  and  a  half  (16,777,220);  at  the  end 
of  two  days  this  bacterium  will  have  multiplied 
to  the  incredible  number  of  281,500,000,000;  at 
the  end  of  three  days  it  will  have  furnished  forty- 
seven  trillions ;  at  the  end  of  about  a  week,  a 
number  which  can  only  be  represented  by  fifty-one 
figures. 

"  In  order  to  render  these  numbers  more  com- 
prehensible, let  us  seek  the  volume  and  the  weight 
which  may  result  from  the  multiplication  of  a 
single  bacterium.  The  individuals  of  the  most 
common  species  of  rod-bacteria  present  the  form 
of  a  short  cylinder  having  a  diameter  of  a  thou- 
sandth of  a  millimeter,  and  in  the  vicinity  of  one  five 
hundredth  of  a  millimetre  in  length.  Let  us  rep- 
resent to  ourselves  a  cubic  measure  of  a  millimetre. 
This  measure  would  contain,  according  to  what  we 
have  just  said,  633,000,000  of  rod-bacteria  with- 
out leaving  any  empty  space.  Now,  at  the  end 
of  twenty-four  hours  the  bacteria  coming  from 
a  single  rod  would  occupy  the  fortieth  part  of  a 
cubic  millimeter;  but  at  the  end  of  the  follow- 
ing day  they  would  fill  a  space  equal  to  442,570 
of  these  cubes,  or  about  a  half  a  litre.  Let  us 
admit  that  the  space  occupied  by  the  sea  is  equal 
to  two-thirds  of  the  terrestrial  surface,  and  that 
its  mean  depth  is  a  mile,  the  capacity  of  the  ocean 
will  be  928,000,000  of  cubic  miles.  The  multipli- 


126       PHYSIOLOGY  OF  THE  BACTERIA. 

cation  being  continued  with  the  same  conditions, 
the  bacteria  issuing  from  a  single  germ  would  fill 
the  ocean  in  five  days." 

Reproduction  by  Spores.  —  The  multiplication 
by  fission,  known  to  the  earliest  microscopists,  has 
been  until  recently  the  only  mode  of  propagation 
admitted  by  the  authors.  Thus  M.  de  Lanessan, 
in  the  excellent  article  which  he  has  devoted  to 
the  bacteria,  says  that  the  marvellous  resources  of 
modern  science  have  not  yet  permitted  us  to  rec- 
ognize any  other  mode  of  propagation  for  these 
organisms. 

However,  M.  Ch.  Robin  had  already,  in  1853, 
indicated  the  presence  in  Leptothrix  buccalis  of 
little  round  bodies,  "  which  are  perhaps  spores." 
Pasteur  has  since,  in  1865,  recognized  that  "  the 
vibrios  of  putrefaction  and  of  butyric  fermentation 
present  a  sort  of  ovule,  or  ovoid  corpuscle,  which 
refracts  light  strongly,  either  in  the  extremity 
or  in  the  body  of  the  articles."  Later,  the  same 
savant,  more  explicitly,  says  clearly  that  these  or- 
ganisms have  two  modes  of  reproduction,  —  by 
fission  and  by  interior  spores  ("  noyaux  "). 

Towards  the  same  epoch,  Hoffmann  also  pointed 
out  a  reproduction  by  free  cellular  formation  in 
some  bacteria.  But  we  must  come  to  the  labors 
of  Cohn,  Billroth,  and  Koch,  in  order  to  find  pre- 
cise observations  in  this  regard. 

The  formation  of  spores  has  been  observed 
in  Bacillus  subtilis  by  Cohn,  Bacillus  anthracis 
by  Koch,  and  in  Bacillus  Amylobacter  by  Van 
Tieghem. 


PLATE  vr 


'€• 


FIG.   i. 


FIG.    2. 


FIG.  4. 


r^-;Q  'O  vO^i 

.  -  io:5>o  OoO    -  - 


FIG.    «;. 


FK;.  3. 


'.r.  V          ' 


PLATE  VI. 

FIG.  1.  —  Micrococci  from  bottom  of  culture-solution  (rabbit- 
bouillon)  inoculated  with  blood  of  septicaemic  rabbit,  containing 
the  same  micrococcus  in  active  multiplication,  as  shown  in  Fig.  3. 
Magnified  1000  diameters  by  Zeiss's  •£$  in.  horn.  ol.  im.  objective. 
Methyl -violet  staining. 

FIG.  2. —  The  same  micrococcus  cultivated  in  chicken-bouillon, 
inoculated  with  human  saliva.  X  1000.  Same  objective  and 
staining. 

FIG.  3.  —  The  same  micrococcus  as  found  in  the  blood  of  a  rab- 
bit, inoculated  with  normal  human  saliva.  (See  p.  237.)  X  1000 
diameters;  Zeiss's  ^  in.  objective. 

FIG.  4.  —  Micrococci  from  culture-solution  (chicken-bouillon) 
inoculated  with  gonorrhceal  pus.  X  1000  diameters ;  Zeiss's  ^  in. 
objective.  Methyl-violet  staining. 

FIG.  5. — Micrococci  from  urine  passed  into  a  sterilized  glass 
vessel  and  allowed  to  stand  five  days,  (covered  with  a  watch-glass 
and  bell-glass;  Lister's  apparatus,  Fig.  5,  p.  176,)  believed  to  be 
identical  with  those  shown  in  Fig.  4,  and  with  Micrococcus  urece, 
Cohn.  (See  description  on  p.  75.)  X  1000  diameters;  Zeiss's 
-£%  in.  objective.  Aniline  brown  staining. 

FIG.  6.  —  Micrococci  from  culture-solution  (malt-extract,)  in- 
oculated with  normal  human  saliva,  probably  identical  with  the 
preceding;  showing  multiplication  in  two  directions.  X  1000,  by 
Zeiss's  ^  in.  objective.  Aniline  brown  staining. 

FIG.  7.  —  Micrococcus  urece,  from  alkaline  urine,  showing  for- 
mation of  "  chaplets," —  torula-chains,  —  by  division  in  one  direc- 
tion only.  X  1000,  by  Zeiss's  ^  in.  objective.  Aniline  brown 
staining. 


128       PHYSIOLOGY  OF  THE  BACTERIA. 

Cohn,  who  had  in  his  first  publications  refused 
to  the  bacteria  the  property  of  reproduction  by 
spores,  thinking  that  the  facts  observed  by  Hoff- 
mann related  to  different  beings,  has  verified  the 
experiments  of  Koch  upon  the  development  of 
B.  anthraeis,  and  has  himself  demonstrated  sim- 
ilar phenomena  in  B.  sublilis. 

In  culture  experiments  made  with  infusion  of 
hay,  we  see,  at  a  certain  moment,  in  the  homo- 
geneous filaments  of  the  Bacilli  very  refractive 
corpuscles  making  their  appearance.  Each  of 
them  becomes  a  spore,  oblong  or  in  the  form 
of  a  short  filament,  highly  refractive,  and  with 
well-defined  outlines.  We  find  the  spores  ar- 
ranged in  a  simple  series  in  the  filaments.  As 
soon  as  the  formation  of  spores  has  terminated, 
the  filaments  can  generally  no  longer  be  distin- 
guished, and  one  would  say  that  the  spores  were 
completely  free  in  the  mucus;  but  their  linear 
arrangement  shows  always  that  they  are  produced 
in  the  interior  of  filaments.  Little  by  little  these 
dissolve,  being  reduced  to  a  fine  powder ;  and  the 
spores  fall  to  the  bottom  of  the  liquid,  where  they 
are  found  in  abundance.  The  germination  of  the 
spore  does  not  seem  to  occur  in  the  same  medium; 
but  if  we  take  a  spore  from  the  deposit  formed  in 
an  infusion  of  boiled  hay,  and  transport  it  into  a 
new  infusion,  we  see  the  spore  swell  up,  and  a  short 
tube  form  itself  at  one  of  its  extremities :  at  this 
moment  it  resembles  a  bacterium  with  a  head. 
Soon  the  very  refractive  body  disappears,  the  tube 
stretches  out  into  a  short  rod  of  Bacillus,  com- 


DEVELOPMENT  OF  THE  BACTERIA.      129 

mences  to  move,  and  becomes  jointed  by  trans- 
verse division. 

Koch,  in  cultivating  the  bacteria  of  charbon  in 
aqueous  humor  from  the  eye  of  the  ox,  has  ob- 
served some  facts  exactly  similar,  both  as  to  pro- 
duction of  spores  in  linear  series  in  the  filaments 
of  Bacillus  anthracis  and  as  to  the  germination  of 
the  spore  and  the  birth  of  a  new  rod. 

According  to  Van  Tieghem,  the  development 
of  Amylobacter  is  as  follows :  "  The  development 
of  a  Bacillus  includes  four  successive  periods.  In 
the  first,  the  body,  cylindrical  and  slender,  recently 
developed  from  a  spore,  stretches  out  rapidly, 
and  is  partitioned ;  the  articles  soon  separate 
(B.  subtilis),  or  remain  united  in  long  filaments 
(B.  anthracis).  This  is  the  stage  of  growth  and 
multiplication,  two  things  which  at  bottom  are 
but  one. 

"Secondly,  the  articles  previously  formed,  having 
ceased  to  elongate  and  divide,  increase  sensibly  in 
magnitude,  becoming  the  seat  of  interior  chemical 
transformations  ;  and  this  increase  in  size  operates 
according  to  circumstances,  in  three  different  man- 
ners, with  some  intermediate  forms.  Sometimes 
it  occurs  uniformly  throughout  the  length  of  the 
article,  which  remains  cylindrical ;  sometimes  it  is 
localized,  either  at  one  extremity,  which  is  swollen 
Iik3  a  tadpole,  or  in  the  middle  of  the  article, 
which  swells  to  a  spindle  shape.  This  is  the  stage 
of  enlargement,  or  of  nutrition,  solitary  and  si- 
multaneous, which  prepares  the  following  state. 

"  In  the  third  period  or  phase  of  reproduction 


130  PHYSIOLOGY  OF  THE  BACTERIA. 

there  is  formed  in  each  article  so  nourished  a 
spherical  or  ovoid  spore>  homogeneous,  highly 
refractive,  having  a  dark  outline.  At  the  same 
time,  the  protoplasm  which  occupies  the  rest  of 
the  cavity  disappears  little  by  little,  and  is  re- 
placed by  a  hyaline  liquid,  which  separates  the 
spore  from  the  membrane;  this  dissolves  in  its 
turn,  and  finally  the  spore  is  set  at  liberty.  If  the 
article  is  swollen  in  tadpole  shape,  it  is  in  the  ter- 
minal swelling  that  the  spore  has  birth  ;  if  it  is 
spindle-shaped,  it  is  near  the  middle ;  if  it  is  cylin- 
drical, it  may  be  at  any  point  whatever,  but  is 
usually  near  one  extremity.  The  spore  when  set 
free  germinates  under  favorable  circumstances. 
At  a  point  where  its  circumference  becomes  pale, 
it  gives  out  a  little  tube  slightly  more  slender 
than  itself,  which  elongates  rapidly  and  divides. 
This  fourth  period  of  development  or  germinative 
phase  brings  us  back  to  our  point  of  departure." 

Sporangia.  —  Finally,  not  only  do  the  bacteria 
develop  spores  in  the  interior  of  their  filaments, 
slightly  modified  in  form,  but  we  may  also  observe 
the  formation  of  a  veritable  sporangium  contain- 
ing many  spores.  The  unpublished  observations 
of  M.  Touissant,  Professor  of  Physiology  in  the 
Veterinary  School  of  Toulouse,  give  this  result, 
which  he  has  kindly  communicated  to  me. 

In  cultivating  spores  of  the  bacteria  of  charbon 
in  the  serum  of  the  blood  of  the  dog,  under  the 
microscope,  in  the  warm  chamber  of  Ranvier, 
Toussaint  has  seen  the  filaments  take  a  transverse 


DEVELOPMENT  OF  THE  BACTERIA.      131 

diameter  almost  double  the  ordinary  diameter, 
then  the  protoplasm  of  the  filament  to  gather 
together  at  certain  points,  —  a  fact  clearly  made 
out,  as  in  the  parts  where  the  protoplasm  was 
wanting  the  bacteria  had  lost  all  refractive  power. 
Finally,  at  a  later  period  the  points  occupied  by 
the  condensed  protoplasm  augment  considerably  in 
volume,  and  form  some  ovoid  organs  more  or  less 
elongated,  or  swollen  into  a  ball,  or  in  the  form 
of  a  gourd  at  one  extremity.  In  the  interior  of 
these  sporangia,  from  three  to  six  spores  afterward 
form,  clearly  defined  and  highly  refractive ;  then, 
finally,  by  breaking  up  of  the  membranous  enve- 
lope the  spores  become  free. 

Toussaint  has  also  followed  in  the  same  appar- 
atus —  moist  and  warm  chamber  of  Ranvier  —  the 
mode  of  germination  of  the  spores.  The  follow- 
ing are  the  most  important  facts :  — 

The  spores  are  at  first  highly  refractive  and 
animated  by  brownien  movements;  at  the  end 
of  half  an  hour  to  an  hour,  at  a  temperature  of 
37  to  40°,  in  urine,  aqueous  humor,  or  serum,  the 
spores  lose  their  refractive  power,  and  their  brown- 
ien movements  cease  almost  entirely;  then  the 
spore  assumes  an  aspect  slightly  granular,  it  be- 
comes elongated  in  the  direction  of  its  greatest 
diameter  (they  are  oval).  After  two  hours  of  culti- 
vation, the  bacterium  has  two  or  three  times  the 
dimensions  of  the  primitive  spore ;  the  elongation 
makes  rapid  progress,  and  four  to  six  hours  from 
the  commencement  of  the  cultivation,  some  may 


132       PHYSIOLOGY  OF  THE  BACTERIA. 

be  found  to  occupy  the  entire  field  of  the  micro- 
scope. From  this  moment  the  phenomena  which 
occur  differ  according  to  the  conditions  in  which 
the  bacteria  are  placed.  Upon  the  edge  of  the 
air-groove  in  the  moist  chamber,  the  bacteria  de- 
velop very  rapidly,  forming  an  interlaced  mass ; 
and  in  sixteen  to  eighteen  hours,  spores  may  be 
seen  to  appear  in  their  interior,  —  above  all,  if  the 
preparation  has  been  exposed  to  light.  Often,  in 
this  case,  the  transverse  partitions  of  the  filament 
cannot  be  seen.  If,  on  the  contrary,  the  bacterium 
has  not  been  exposed  to  light,  the  spores  are  a 
longer  time  in  showing  themselves  (ten  or  twelve 
hours  more),  and  almost  always  division  of  the 
filament  precedes  their  formation.  In  that  case, 
a  spore  usually  appears  at  each  end  of  the  seg- 
ment in  such  a  manner  that  the  spores  belonging 
to  two  successive  segments  are  nearer  to  each 
other  than  those  in  the  same  segment.  Often, 
also,  a  spore  aborts  in  a  segment  (Toussaint). 

We  have  seen  above,  in  speaking  of  the  res- 
piration of  bacteria,  that  the  same  observer  has 
noted  in  the  course  of  his  experiments  some  phe- 
nomena proving  the  evident  influence  of  oxygen 
upon  the  development  of  Bacillus.  It  is  the  same 
for  the  formation  of  spores.  And  upon  this  point 
Toussaint  makes  the  very  just  remark  that  the 
phenomena  occur  in  a  different  manner  in  culture 
experiments  and  in  the  human  organism.  In  char- 
bon,  the  bacteria  never  form  spores.  They  remain 
always  relatively  short,  even  in  the  points  where 
they  form  extra-vascular  masses,  and  where  conse- 


DEVELOPMENT  OF  THE  BACTERIA.      133 

quently  we  cannot  invoke  the  movements  of  the 
liquid  in  order  to  explain  their  division.  The 
bacteria  of  charbon,  then,  take  but  little  oxygen 
from  the  tissues :  they  do  not  vegetate  luxuriantly 
in  the  organism;  and  certainly,  if  we  judge  by  a 
calculation  necessarily  approximative,  their  devel- 
opment is  seven  or  eight  times  less  rapid  than  in 
the  strongly  oxygenated  serum  of  culture  experi- 
ments (Toussaint). 

Polymorphism.  —  The  spores  of  which  we  have 
traced  the  genesis  constitute  those  germs  of  which 
the  origin  has  for  a  long  time  been  misunder- 
stood,—  those  permanent  spores  or  durable  spores 
(Dauersporen),  thus  called  because  of  their  re- 
markable degree  of  resistance  to  temperature, 
desiccation,  and  all  the  agents  which  kill  adult 
bacteria  or  arrest  their  development. 

These  "  organs  "  are  disseminated  in  great  num- 
bers in  various  media  under  the  form  of  little 
rounded  corpuscles  absolutely  similar  to  the  micro- 
cocci  from  which  it  is  absolutely  impossible  to 
differentiate  them.  It  is,  indeed,  very  probable 
that  the  greater  part,  if  not  all  of  these  organisms, 
are  the  spores  of  filiform  bacteria. 

In  the  impossibility  of  recognizing  these  forms 
so  nearly  related,  of  referring  them  to  such  or 
such  a  determined  organism,  the  attempt  has  been 
made  to  cultivate  them,  in  order  to  follow  their 
development.  We  have  just  seen  the  results  of 
this  cultivation  for  the  Bacillus  ;  but,  in  the  hands 
of  the  greater  number  of  experimenters,  the  re- 


134  PHYSIOLOGY  OF  THE  BACTERIA. 

suits  of  such  culture  experiments  are  far  from 
being  so  certain.  Not  having  succeeded  in  re- 
moving them  completely  from  the  invasion  of  for- 
eign germs,  the  greater  number  have  seen  the 
most  diverse  forms  develop  themselves,  and  from 
this  have  inferred  the  most  remarkable  transfor- 
mations. 

Thus,  Hallier  pretends  to  have  observed  the 
transformation  of  Micrococcus  into  various  fungi, 
such  as  Mucors,  Ustilago,  etc.  The  M.  of  vaccinia 
comes  from  Torula  rufescens,  which  is  itself  a 
phase  of  development  of  Ustilago  carbo ;  the  M. 
of  human  variola  is  derived  from  a  fungus  having 
sporangia  and  pycnidia,  related  to  Stemphylium 
sporidesmium ;  that  of  the  variola  of  animals 
from  Cladosporium  (Pleospora)  herbarum ;  the 
M.  of  the  blood  of  scarlatina  belongs  to  the 
g.  Tilletia;  those  of  glanders  and  of  syphilis 
from  a  Coniothecium,  etc.  In  the  same  way  Letz- 
erich  has  referred  the  M.  of  diphtheria  to  another 
Tilletia,  the  T.  diphtkerica. 

The  transformation  of  bacteria  into  "  levures  " 
(yeast  fungi),  and  these  into  Penicillium,  has  been 
admitted  by  Hallier,  Trecul,  and  others.  But  the 
researches  of  Brefeld  and  de  Seynes  have  shown 
us  that  this  is  far  from  being  demonstrated  ;  in- 
deed, in  his  numerous  cultivations,  de  Seynes  has 
never  been  able  to  verify  such  an  affiliation ;  and 
Nageli  in  his  turn  has  never  been  able  to  obtain 
a  transformation  of  schizomycetes  into  budding 
fungi. 

It  is  the  same  as  regards  the  transformation  of 


DEVELOPMENT  OF  THE  BACTERIA.      135 

bacteria  into  moulds  and  mildews.  In  some  recent 
cultivations  of  moulds,  made  with  care,  Nageli  has 
never  observed  the  formation  of  schizomycetes, 
and  reciprocally.  Are  we  not  permitted  to  be- 
lieve, now  that  we  know  of  the  formation  of 
sporangia  among  the  bacteria,  that  the  micro- 
scopists  who  sustain  a  polymorphism  so  extended, 
have  taken  these  organs,  of  which  they  have  not 
been  able  to  follow  exactly  the  development,  for 
the  sporangia  of  Mucorini?  This  explanation  is 
the  more  admissible  as  Trecul  has  seen  the  bac- 
teria "  swell  up,  and  transform  themselves  sepa- 
rately," a  phenomenon  quite  identical  to  that  ob- 
served by  Toussaint. 

En  resume.  The  only  change  of  form  well 
demonstrated  in  the  present  state  of  science,  and 
the  only  one  which  can  be  compared  to  natural 
polymorphism,  such  as  it  exists  in  a  great  number 
of  fungi,  consists  in  the  transformation  of  spores 
into  Bacteria,  Bacteridia,  Vibrios,  etc.,  and  in  the 
different  modes  of  grouping  that  the  cells  of  bac- 
teria take  in  becoming  zooglcea,  mycoderma,  lepto- 
thrix,  etc.  To  go  further  would  be  to  lack  pru- 
dence and  scientific  criticism. 


136  PHYSIOLOGY  OF  THE  BACTERIA. 


CHAPTER  II. 

DEVELOPMENT  OF  THE  BACTEKIA  IN 
DIFFERENT  MEDIA. 

IN  studying  the  conditions  of  life  and  of  develop- 
ment of  bacteria  in  the  different  media,  natural 
and  artificial,  in  which  they  are  met,  we  will  con- 
sider the  actions  which  they  determine  (or  that 
they  accompany)  as  particular  cases  of  their  nutri- 
tion and  of  their  reproduction.  We  will  con- 
stantly take,  then,  their  normal  physiology  as  our 
point  of  departure ;  and  we  will  try  to  explain  in 
this  way  the  phenomena,  so  diverse,  with  which  they 
are  associated,  —  fermentations,  putrefactions,  con- 
tagion of  infectious  maladies,  etc. 

It  is  especially  interesting  to  study  the  role  of 
bacteria  in  non-nitrogenized  chemical  media,  where 
they  accompany  the  phenomena  called  fermenta- 
tion, properly  so  called ;  in  nitrogenized  media, 
vegetable  or  animal,  which  they  transform,  as  a 
result  of  special  fermentations,  which  constitute 
putrefaction ;  in  the  human  organism,  where  they 
accompany  frequently,  if  not  always,  the  develop- 
ment of  certain  affections  having  special  charac- 
ters. This  will  be  the  object  of  so  many  para- 
graphs 


THE  BACTERIA  IN  DIFFERENT  MEDIA.  137 


§  1.  —  HOLE  OF  BACTERIA  IN  FERMENTATIONS. 

We  say  that  a  liquid  is  fermenting  whenever 
modifications  occur  in  its  chemical  constitution,  as 
a  result  of  the  nutrition  of  organized  beings. 

Two  kinds  of  fermentation  are  commonly  distin- 
guished. In  the  first  group  (false  fermentations) 
are  arranged  those  which  are  produced  by  soluble 
quarternary  substances  (diastase,  soluble  ferments) 
secreted  by  living  cells,  from  which  they  may  be 
separated  in  order  to  study  their  action  upon  fer- 
mentable liquids.  This  action  is  comparable  to  that 
of  certain  mineral  acids,  which  operate  in  the  same 
manner,  either  by  the  breaking  up  of  molecules 
with  addition  of  water  or  by  the  phenomena  of 
hydration.  Veritable  chemical  reagents,  when 
these  substances  are  once  precipitated  from  their 
solutions,  purified  and  dried,  they  preserve  their 
properties  indefinitely.  A  sufficient  elevation  of  tem- 
perature seems  to  destroy  the  edifice  of  their  mol- 
ecule ;  for  they  lose  all  their  specific  power  after 
having  been  subjected  to  a  temperature  more  or  less 
elevated,  but  always  inferior  to  100°  (212°  Fah.). 

In  the  second  group  (true  fermentations)  are 
joined  all  the  phenomena  of  chemical  modifica- 
tion which  appear  intimately  united  to  the  devel- 
opment of  inferior  organisms,  —  algse  or  fungi 
(figured  ferments).  Compressed  oxygen  by  kill- 
ing these  ferments,  and  chloroform  by  suspending 
their  vital  functions,  arrest  the  progress  of  these 
fermentations,  while  the  same  agents  do  not  mod- 


138  PHYSIOLOGY  OF  THE  BACTERIA. 

ify  at  all  the  action  of  soluble  ferments.  Accord- 
ing to  Duinas,  borax  has,  on  the  contrary,  the 
property  of  entirely  destroying  the  activity  of 
soluble  ferments  without  absolutely  preventing 
certain  true  fermentations, — for  example,  the  al- 
coholic fermentation  of  glucose.  We  will  see  fur- 
ther on  that  this  property  of  borax  has  been 
utilized  in  the  treatment  of  catarrh  of  the  blad- 
der and  of  certain  virulent  affections. 

Although  at  first  view  these  two  groups  of  phe- 
nomena seem  very  different,  they  may,  however, 
be  compared  the  one  with  the  other.  Without 
speaking  of  the  ammoniacal  fermentation  of  urine, 
which,  as  we  shall  shortly  see,  may  be  arranged  in 
either  of  these  groups,  we  may  admit  that  the  only 
difference  between  these  two  series  of  chemical 
modifications  consists  in  the  fact  that  in  one  case 
the  true  fermentations  being  the  last  term  in  the 
interior  nutrition  of  the  cell  have  their  seat  in 
the  interior  of  the  cell  itself ;  while  in  the  other 
the  first  terms  of  nutrition  are  always  extra-cellu- 
lar phenomena,  having  for  effect,  as  Cl.  Bernard 
has  shown,  to  render  assimilable  or  diffusible  in  the 
interior  of  the  organism  the  aliment  necessary  to 
the  development  of  every  organized  being  (trans- 
formation of  starch  into  glucose,  of  sugar  into 
glucose,  emulsion  of  fats,  liquefaction  of  albumi- 
noid substances). 

The  study,  from  a  chemical  point  of  view,  of 
these  phenomena  of  nutrition,  of  these  fermenta- 
tions, since  such  is  their  name,  has  not  yet  made 
much  progress,  and  it  would  be  difficult  to  make  a 
rational  classification  of  them  in  the  present  state 


THE  BACTERIA  IN  DIFFERENT  MEDIA.          139 

of  our  knowledge.  I  will  not  then  seek  to  clas- 
sify them,  but  will  content  myself  with  describ- 
ing them  successively,  commencing  with  the  best 
known.  I  shall  only  speak  of  the  fermentations 
caused  by  the  development  of  bacteria,  leaving, 
consequently,  the  fermentation  which  has  been 
best  studied,  —  the  alcoholic.  I  adopt  the  follow- 
ing order : — 

1.  Acetic  fermentation  of  alcohol. 

2.  Ammoniacal  fermentation  of  urine. 

3.  Lactic,  viscous,  and  butyric  fermentations  of  sugar. 

4.  Putrefaction,  or  nitrification. 

Acetic  fermentation.  —  The  transformation  of 
wine  into  vinegar  is  a  phenomenon  long  known 
and  utilized.  From  a  chemical  point  of  view,  this 
transformation  is  due  to  oxydation  of  the  alcohol. 
The  following  formula  represents  this  reaction  :  — 

C2H6O  +  O2  =  C2H4O2  +  H2O. 

The  agent  of  this  oxydation  is  a  micro-organism 
called  Mycoderma  aceti.  It  belongs  to  the  group 
of  the  microbacteria,  and  we  have  already  given 
the  botanical  description  of  it  (page  83) ;  but  its 
development  presents  some  interesting  peculiar- 
ities which  we  think  it  proper  to  indicate  in  the 
language  of  M.  Duclaux :  — 

"  These  little  beings  reproduce  themselves  with 
such  rapidity  that  by  placing  an  imperceptible  germ 
upon  the  surface  of  a  liquid  contained  in  a  vat 
having  a  surface  of  one  square  metre,  we  may 
see  it  covered,  in  from  twenty-four  to  forty-eight 
hours,  with  a  uniform  velvety  veil.  If  we  suppose 


140  PHYSIOLOGY  OF  THE  BACTERIA. 

that  there  are  three  thousand  cells  in  a  square  mil- 
limetre, which  is  below  the  truth,  this  will  give 
for  the  vat  three  hundred  milliards  of  cells  pro- 
duced in  a  very  short  time." 

"  The  Mycodermi  aceti  is  not  always  the  same. 
Usually  it  forms  upon  the  surface  of  a  liquid  a 
soft-looking  veil,  smooth  at  first,  then  wrinkled, 
which  is  with  difficulty  submerged  and  moistened. 
If  a  glass  rod  is  plunged  into  the  liquid,  it  pierces 
this  veil ;  and  when  it  is  withdrawn,  a  portion  re- 
mains attached  to  the  rod ;  aaid  the  opening  made 
immediately  disappears,  being  occupied  by  the  veil 
which  seems  never  to  have  room  enough  in  which 
to  extend  itself.  In  some  unpublished  experi- 
ments I  have  frequently  observed  another  form  of 
veil,  dryer,  finer,  and  sometimes  showing  prismatic 
colors.  This  veil  does  not  wrinkle,  but  is  covered 
with  crossed  undulations,  having  sharp  edges, 
which  recall  the  surface  of  a  honeycomb.  Sowed 
upon  the  surface  of  various  liquids,  it  reproduces 
itself  identically,  and  it  is  difficult  not  to  consider 
it  a  different  form  of  the  preceding.  Finally,  I 
have  also  met  a  species  of  mycoderma  producing 
well-developed  veils,  but  having  scarcely  any  acet- 
ifying power,  and  reproducing  itself  with  this 
character." 

"It  is  difficult  to  distinguish  these  forms  the  one 
from  the  other,  by  the  microscope,  because  of  their 
minuteness.  We  may,  however,  say  that  the  second 
which  I  have  described  is  sensibly  smaller  than 
the  first,  and  the  third  more  attenuated  than  either 
of  the  others.  However,  the  differences  are  feeble." 

This  veil  is  called  the  mother  of  vinegar.     The 


THE   BACTERIA  IN   DIFFERENT   MEDIA.          141 

liquid  in  which  this  mycoderma  is  cultivated  should 
be  a  little  acid,  containing  one-half  per  cent  of 
acetic  acid,  for  example.  Under  these  conditions 
the  Mycoderma  vini  (a  species  of  Saccharomycete), 
the  formation  of  which  should  be  avoided,  finds 
conditions  unfavorable  to  its  existence.  Indeed, 
this  second  organism,  commonly  called  flowers  of 
wine,  has  an  action  quite  different  from  that  of 
the  Mycoderma  aceti.  It  consumes  the  alcohol 
entirely,  transforming  it  into  water  and  carbonic 
acid  :  it  also  consumes  the  acetic  acid.  We  must 
sow  the  M.  aceti,  if  we  do  not  wish  to  see  the  M. 
vini  develop  in  its  place,  as  the  germs  of  the  latter 
seem  more  widely  diffused  in  the  air. 

In  order  that  the  acetification  may  occur,  the 
oxygen  of  the  air  is  necessary.  Once  submerged, 
the  M.  aceti  develops,  but  no  longer  produces 
acetic  acid.  It  is  even  probable  that  it  consumes 
the  acetic  acid  already  formed,  reducing  it  to  the 
state  of  water  and  carbonic  acid.  It  is  the  same 
when,  developing  upon  the  surface,  it  has  trans- 
formed all  the  alcohol.  "  In  effect,  it  is  not  then 
arrested  in  its  work  ;  and  without  changing  form 
or  mode  of  action,  it  carries  the  oxygen  of  the  air 
to  the  acetic  acid  which  it  has  produced,  transform- 
ing it  into  carbonic  acid  and  water.  If  we  add  some 
alcohol  to  the  liquid,  the  phenomena  change :  the 
acid  is  respected,  and  the  alcohol  is  transformed 
anew  into  acetic  acid  "  (Duclaux).  According  to 
the  experiments  of  Mayer,  the  maximum  of  aceti- 
fying power  is  obtained  between  20°  and  30°  (68° 
to  86°  Fah.),  and  this  power  is  lost  below  10°  (50° 
Fah.)  and  above  35°  (95°  Fah.). 


142  PHYSIOLOGY   OF  THE  BACTERIA. 

Ammoniacal  Fermentation  of  Urine.  —  When 
urine  is  freely  exposed  to  the  air,  we  perceive  at 
the  end  of  a  short  time  that  it  has  become  strongly 
ammoniacal.  The  urea  is  transformed  into  carbon- 
ate of  ammonia  by  the  addition  of  water :  — 

CO(NH2)2  +  H20  =  CO2  +  2NH3. 

Miiller  suspected  that  the  deposit  of  altered 
urine,  of  which  Jacquemart  had  already  recognized 
the  particular  activity,  was  an  organized  ferment, 
but  this  was  only  an  induction  drawn  from  the 
analogy  with  beer  yeast.  Pasteur  showed  that 
this  sediment  is  formed  of  a  mass  of  spherical 
globules,  united  in  chaplets,  which  he  considers  the 
agent  of  ammoniacal  fermentation.  These  glob- 
ules are  Micrococcus  urece,  Cohn,  which  we  have 
already  described  (page  75). 

This  bacterium  lives  in  the  interior  of  the  liquid, 
and  not  on  the  surface  like  the  Mycoderma  aceti. 
Acidity  is  an  obstacle  to  its  development ;  alkalin- 
ity, on  the  contrary,  favors  it  within  certain  limits. 
Van  Tieghem  has  even  seen  the  fermentation  con- 
tinue until  the  liquid  contained  thirteen  per  cent 
of  carbonate  of  ammonia. 

What  is  the  mechanism  of  this  fermentation  ? 

M.  Musculus  has  shown  that  we  may  obtain 
from  altered  urine  a  soluble  ferment  upon  adding 
to  it  highly-concentrated  alcohol :  a  precipitate  is 
formed,  which  may  be  filtered  and  dried.  This 
precipitate,  not  at  all  organized,  transforms  urea 
into  carbonate  of  ammonia.  A  temperature  of 
80°  (176°  Fah.)  destroys  it.  This  diastase  appears, 


THE  BACTERIA  IN  DIFFERENT  MEDIA.          143 

then,  to  be  a  secretion  of  the  Micrococcus  urece ; 
and  perhaps  the  role  of  the  bacteria  is  limited,  in 
the  phenomena  of  fermentation,  to  the  formation  of 
this  secretion  alone.  The  ammoniacal  transforma- 
tion of  urine  would  consequently  enter  into  the 
group  of  fermentations  by  the  varieties  of  diastase. 

According  to  Arnold  Hiller,  if  carbolic  acid  be 
added  to  urine,  it  does  not  become  alkaline ;  on 
the  contrary,  the  acidity  is  even  augmented,  and 
that  notwithstanding  a  considerable  number  of 
bacteria  which  develop  in  it.  Has  the  carbolic 
acid  killed  the  Micrococcus  urece,  leaving  the  field 
free  to  other  organisms  capable  of  living  in  an 
acid  medium,  and  of  producing  other  transforma- 
tions of  the  constituents  of  the  urine  ?  In  the 
•memoir  which  we  here  cite,  the  author,  resuscitat- 
ing the  ancient  opinion  of  Liebig,  wishes  to  dem- 
onstrate that  the  decomposition  of  dead  organic 
matters,  and  putrefaction  in  general,  are  phenom- 
ena purely  chemical,  —  these  decompositions  being 
determined  by  the  presence  of  organic  substances, 
themselves  undergoing  transformations. 

We  will  not  stop  to  consider  these  views,  long 
since  refuted :  the  experiments  upon  which  they 
are  founded  are  easily  criticised.  It  is  sufficient 
for  me  to  say  that  they  are  in  formal  opposition 
with  all  the  observations  contained  in  modern 
works  upon  this  question. 

It  is  especially  in  relation  to  ammoniacal  fer- 
mentation that  the  question  of  spontaneous  gen- 
eration has  been  discussed.  We  have  already 
seen  the  results  arrived  at,  and  will  not  return  to 


144  PHYSIOLOGY  OF  THE  BACTERIA. 

this  subject.  Let  us,  however,  mention  before 
closing  an  interesting  work  by  MM.  Cazeneuve 
and  Livon,  in  which  are  reported  some  experiments 
which  prove  that  urine  never  ferments  in  a  healthy 
bladder. 

Lactic,  Butyric,  and  Viscous  Fermentations  of 
Sugars.  —  Saccharine  liquids,  left  to  themselves, 
are  susceptible  of  divers  fermentations,  which  may 
occur  separately  or  simultaneously.  Those  which 
have  been  best  studied  are  three,  —  the  lactic,  the 
butyric,  and  the  viscous  fermentations.  We  will 
describe  them  successively. 

1.  Lactic  Fermentation.  —  Under  the  probable 
influence  of  a  bacterium  (ferment  lactique  of  Pas- 
teur) glucose  and  the  substances  susceptible  of 
furnishing  it,  such  as  mannite,  malic  acid,  etc.,  are 
transformed  into  lactic  acid. 

From  a  chemical  point  of  view,  there  is  in  this 
nothing  more  than  a  molecular  change,  lactic  acid 
having  the  same  composition  as  glucose. 

Taken  in  mass,  the  lactic  ferment  resembles 
beer-yeast ;  its  consistence  is,  however,  a  little  more 
viscous,  and  its  color  more  gray.  But  under  the 
microscope,  the  aspect  is  very  different,  as  we  have 
seen  in  describing  Bacterium  lineola. 

An  interesting  point  concerning  this  fermenta- 
tion is  the  action  of  acids  upon  the  bacteria  which 
produce  it  (presumably).  As  soon  as  the  medium 
becomes  acid,  even  by  the  lactic  acid  produced,  the 
transformation  is  arrested.  It  resumes  its  course, 
if  chalk  or  carbonate  of  soda  is  added  to  the 
liquid. 


THE  BACTERIA  IN  DIFFERENT   MEDIA.          145 

The  most  suitable  temperature  seems  to  be  35° 
(95°  Fah.). 

We  know  but  little  about  this  fermentation. 
"  It  merits,  however,  to  be  better  studied.  It 
is  this  which  causes  the  spontaneous  coagulation 
of  milk :  sugar  of  milk  is  transformed  into  lactic 
acid,  which  coagulates  the  caseine.  We  often  see  it 
occur  in  beef  juice  or  in  sour  starch  water;  it  must 
play  a  part  in  the  formation  of  sour  krout,  and 
intervenes  very  certainly,  and  perhaps  more  than 
the  alcoholic  fermentation,  in  the  preparation  of 
bread.  Finally,  it  very  easily  invades  beer,  which 
of  our  domestic  drinks  is  most  exposed,  because  of 
its  slight  acidity,  to  become  the  seat  of  this  fer- 
mentation. All  of  these  facts  render  it  interest- 
ing, so  much  the  more  as  it  is  rarely  exempt  from 
complication,  and  is  frequently  accompanied,  for 
example,  by  a  commencement  of  butyric  fermenta- 
tion, far  more  disagreeable  in  its  products  "  (Du- 
el aux). 

2.  Butyric  Fermentation.  —  This  is,  in  fact,  al- 
ways preceded  by  a  lactic  transformation,  and  it  is 
by  an  ulterior  modification  that  the  lactic  acid 
produces  the  butyric  acid.  The  organism  which 
accompanies  it  is  a  bacterium  very  nearly  allied 
to  Bacillus  subtilis,  Cohn. 

The  reaction  represented  by  the  phenomena, 
from  a  chemical  point  of  view,  is  the  follow- 


ing:— 


2CSH6O3  =  C4H8O2 

lactic  ac.  butyric  ac. 


146       PHYSIOLOGY  OF  THE  BACTERIA. 

According  to  Pasteur  the  butyric  ferment  be- 
longs to  his  class  of  anaerobies. 

This  fermentation  resembles  putrefaction  in  a 
great  many  particulars.  Indeed  some  authors  in- 
clude it  under  the  same  head. 

3.  Viscous  Fermentation.  —  Wines  often  change 
so  that  they  contain  a  mucilaginous  substance  and 
mannite.  This  viscous  matter  has  the  same  com- 
position as  gum  or  dextrine  (C6H1005)  ;  at  the 
same  time  it  disengages  carbonic  acid. 

In  the  fermenting  liquid,  we  find  an  organism 
which  is  not  yet  sufficiently  studied.  "  There  are 
chaplets  of  little  spherical  bodies,  of  which  the  di- 
ameter varies  sensibly,  according  to  the  kind  of 
wine  attacked  by  this  malady  (Pasteur). 

Pasteur  has  proposed  the  following  formula :  — 

25(C12H22O11)  +  25H2O  =  12(C12H20O10)  + 

gum. 

24(C6HI4O6)  +  12C02  +  12H2O. 

mannite. 

which  represents  the  phenomena  well  enough  as  it 
usually  occurs.  There  is  produced  in  the  vicinity 
of  51.09  of  mannite  and  45.5  of  gum  for  one  hun- 
dred parts  of  sugar.  But  sometimes  the  gum  ex- 
ceeds the  mannite  in  quantity.  In  this  case, 
according  to  Pasteur,  we  can  always  verify  in  the 
liquid  the  presence  of  a  larger  ferment  of  a  differ- 
ent nature ;  and  the  same  author  adds  that,  per- 
haps, in  this  case  the  increased  production  of  gum 
results  from  the  presence  of  this  second  ferment, 
which  transforms  the  sugar  only  into  gum,  without 


THE   BACTERIA  IX   DIFFERENT   MEDIA.  147 

any  correlative  formation  of  mannite.  But  this 
ferment  has  never  been  isolated.  M.  Monoyer  has 
explained  the  variation  in  the  proportion  of  gum 
in  another  manner  (see  his  thesis  for  the  doctorate 
in  medicine.  urg,  1862). 

"White  wines  are  more  subject  than  red  wines  to 
this  fermentation,  called  graisse  des  vi?is.  Accord- 
ing to  M.  Francois,  the  absence  of  tannin  in  the 
white  wines  is  the  cause  of  this  disease,  and  it 
may  be  prevented  by  adding  this  substance.  This 
remedy  is  even  very  highly  appreciated  in  cham- 
pagne, according  to  Pasteur.  What  is  the  exact 
action  of  the  tannin  upon  the  gummy  ferment  ? 
The  only  means  of  knowing  is  by  cultivating  this 
ferment  in  a  state  of  purity  and  treating  it  with 
this  agent. 

We  have  united  together  the  lactic,  butyric,  and 
viscous  ferments,  because  all  three  manifest  them- 
selves in  the  same  liquids, — wines,  beer,  sweetened 
water,  etc. ;  and  because  they  have  for  effect  the 
transformation  of  glucose.  We  ought  to  say  a 
word  here  of  some  other  inferior  organisms,  per- 
haps bacteria,  observed  also  in  the  same  liquids, 
but  which  have  not  been  as  well  studied.  Not 
only  are  they  not  known  systematically,  but  we 
do  not  know  precisely  what  is  their  chemical  ac- 
tion upon  the  elements  of  the  medium  which 
nourishes  them.  I  shall  only  enumerate  them. 

1.  Ferment  of  Turned  Beer  (Pasteur).  —  -'-These 
are  rods  or  filaments,  simple  or  articulated  into 
chains  of  variable  length,  of  about  1  p.  diameter. 


148  PHYSIOLOGY  OF  THE  BACTERIA. 

A  high  power  shows  them  divided  into  a  series  of 
shorter  rods,  scarcely  born,  not  yet  mobile  at  the 
articulations,  which  are  scarcely  indicated." 

2.  Micrococcus  of  a  beer,  having  a  particular 
acidity,  distinct  from  that  of  beer  pique,  having 
an  acetic  odor.  "  It  consists  of  grains  resembling 
little  spherical  points  jointed  by  pairs  or  in  fours 
square  "  (Pasteur),  etc. 

§  2. —  HOLE  OF  THE  BACTERIA  IN  PUTREFACTION 
AND  NITRIFICATION. 

While  in  the  fermentations  which  we  have  just 
passed  rapidly  in  review,  we  have  always  been 
able  to  study,  at  least  summarily,  the  chemical 
action  of  the  different  organisms,  we  are  now 
about  to  find  ourselves  in  presence  of  phenomena 
far  more  complex.  We  will  have  to  consider  a 
great  number  of  these  vegetables  at  work,  without 
its  being  possible  to  assign  to  each  its  role,  or  to 
say  what  is  its  function.  The  agent  of  the  nitric 
fermentation  has  not  as  yet  even  been  seen,  and  it 
is  only  by  analogy  that  we  class  this  nitrification 
with  the  true  fermentations. 

It  is  not  only  because  of  the  obscurity  which 
still  exists  in  regard  to  a  great  number  of  peculiar- 
ities of  these  two  phenomena,  that  we  have  united 
them  in  the  same  study.  From  the  point  of  view 
of  the  circulation  upon  the  surface  of  our  globe 
of  the  elements  essential  to  the  constitution  of 
organisms,  they  play  an  analogous  role,  although 
opposite  the  one  to  the  other. 


THE  BACTERIA  IN  DIFFERENT   MEDIA.          149 

Let  us  consider,  for  example,  nitrogen  in  plants. 
This  element,  of  which  the  atmosphere  is  the  res- 
ervoir, does  not  enter  directly  into  combination,  as 
does  oxygen,  with  the  other  elements  which  with 
it  are  to  constitute  the  immediate  principles  of  the 
tissues.  The  chemical  properties  of  nitrogen  may 
be  characterized  in  two  words,  —  great  resistance 
to  entering  into  combination  when  it  is  free,  and 
great  facility,  on  the  contrary,  in  passing  from  one 
combination  to  another  when  once  it  has  associated 
itself  with  other  elements. 

The  circulation  of  nitrogen  in  a  state  of  com- 
bination upon  the  surface  of  the  globe  is  also  an 
interesting  question  of  general  physics,  as  well  as 
the  circulation  of  carbonic  acid,  of  water,  and  of 
the  air. 

Let  us  seek  to  sketch  the  march  of  this  cir- 
culation. 

Whence  comes  the  ammonia  which  is  found  in 
the  sea,  in  the  clouds  which  come  to  us  from  equa- 
torial regions,  in  the  dust  of  the  air  ?  The  only 
known  source  is  the  fermentation  of  organic  mat- 
ters out  of  reach  of  the  oxygen  of  the  air.  It  is 
to  this  sort  of  fermentation  that  we  owe  the  for- 
mation of  peat  and  the  immense  masses  of  com- 
bustible minerals  which  have  formed  during  nearly 
all  the  geological  periods.  We  see  this  sort  of  fer- 
mentation develop  itself  when  we  expose  an  or- 
ganic liquid  to  the  air,  but.  only  in  the  inferior 
part  of  the  liquid,  the  oxygen  which  is  dissolved 
near  the  surface  being  arrested  in  the  superficial 
zone,  where  a  very  different  fermentation  occurs. 


150  PHYSIOLOGY  OF  THE  BACTERIA. 

The  latter  is  essentially  oxidizing  ;  the  material  is 
almost  completely  burnt,  forming  water  and  car- 
bonic acid ;  at  the  inferior  part,  on  the  contrary,  a 
reduction  is  produced  so  energetic  that  hydrogen 
is  disengaged.  The  metallic  sulphates  are  there 
transformed  into  sulphites,  and  even  crystals  of 
sulphur  are  sometimes  found  (see  the  history  of 
the  Beggiatoa,  page  91). 

We  see  then  the  source  of  the  ammonia,  which, 
distributed  upon  the  soil  by  the  winds  and  the  rains, 
becomes  a  powerful  fertilizer.  Now,  vegetables  do 
not  absorb  nitrogen  under  the  form  of  ammonia,  but 
under  the  form  of  nitric  acid.  How  is  this  transform- 
ation of  ammonia  into  nitric  acid  effected  ?  The 
observations  of  Erdmann,  Mensel,  and  T.  Phipson 
show  that  in  the  phenomena  of  destructive  putre- 
faction, nitric  acid,  far  from  being  produced,  is  on 
the  contrary  reduced  to  the  state  of  nitrous  acid ; 
on  the  other  hand,  Th.  Schloesing  and  A.  Miintz 
conclude  from  their  experiments  that  in  the  pu- 
trefactions essentially  oxidizing  produced  by  Peni- 
cillum  glaucum,  Aspergillus  niger,  Mucor  mucedo, 
etc.,  there  is  no  formation  of  nitric  acid.  But, 
according  to  these  authors,  nitrification  is  a  spe- 
cial phenomenon  which  takes  place  in  every  soil 
sufficiently  loose  to  permit  a  free  circulation  of  air, 
and  of  which  the  agent  is  a  micro-organism.  This 
organism  has  not  yet  been  perceived,  it  is  true ; 
and  it  is  evident  that  it  would  be  difficult  to  seek 
and  observe,  because  of  its  peculiar  situation. 

But  the  action  of  chloroform  upon  nitrification 
tends  to  prove  that  the  agent  of  this  process  is 


THE  BACTERIA  IN  DIFFERENT  MEDIA.          151 

truly  an  organized  ferment.  Indeed,  chloroform, 
this  anaesthetic,  suspends  nitrification,  and  seems 
even  to  kill  the  ferment. 

Leaving,  then,  this  phenomenon,  but  little 
known,  we  may  distinguish  in  the  agents  of  pu- 
trefaction, or  more  generally  of  fermentation,  two 
groups  of  micro-organisms,  —  one  oxidizing,  the 
other  reducing. 

The  first  are  observed  upon  the  surface  of 
liquids  undergoing  putrefaction.  We  may  distin- 
guish a  great  number  of  forms, — Bacterium  termo, 
Monas  crepusculum,  Spirillum,  etc.  We  ought 
also  to  include  Mycoderma  aceti,  which,  like  the 
others,  vegetates  on  the  surface  of  liquids,  and 
a  great  number  of  organisms  of  which  we  cannot 
speak  here. 

The  second  are  met,  on  the  contrary,  in  the 
interior  of  liquids  or  of  fermentable  bodies ;  they 
are  analogous  to  the  butyric  and  lactic  ferments, 
and  perhaps  to  the  other  agents  of  diseases  of 
wine  and  beer  previously  enumerated. 

En  resume,  the  little  beings  which  we  have  been 
considering  have  an  important  role:  they  cause 
the  return  of  dead  organic  matter  to  the  atmos- 
phere and  to  water. 

"Without  them,  organic  matter,  even  exposed 
to  the  air,  would  not  be  destroyed  or  would  be 
transformed  with  extreme  slowness,  in  consequence 
of  a  slow  combustion  produced  by  oxygen.  With 
them,  on  the  contrary,  its  destruction  takes  a 
rapid  march  and  becomes  complete.  If,  then,  the 
equilibrium  is  maintained  between  living  nature 


152  PHYSIOLOGY  OF  THE  BACTERIA. 

and  dead  nature,  if  the  air  has  always  the  same 
composition,  if  the  waters  are  always  equally  fer- 
tilizing, it  is  thanks  to  the  infinitely  minute  agents 
of  fermentation  and  putrefaction"  (Duclaux). 

But  the  role  of  bacteria  is  not  limited  to  this. 
"  They  invade  also  the  living  organism,"  says  Du- 
claux, "  and  bring  in  their  attack  this  double  char- 
acter of  infinite  smallness  in  the  apparent  means 
and  powerful  destructive  energy  in  the  results. 
From  this  source  come  diseases  of  which  medicine, 
not  long  since,  did  not  know  the  cause,  and  which 
she  only  commences  to  refer  to  their  veritable 
origin.  For  those  who  are  au  courant  with  the 
first  steps  which  she  has  made  in  this  new  line  of 
research,  with  the  fecundity  of  her  first  glimpses, 
with  the  richness  of  her  first  results,  it  is  not 
doubtful  that  she  will  soon  succeed  in  demonstrat- 
ing the  parasitic  nature  of  the  gravest  epidemic 
maladies  " 


PART  THIRD. 

TECHNOLOGY. 


PART  FOURTH. 

GERMICIDES   AND   ANTISEPTICS. 


PART  FIFTH. 

BACTERIA   IN    INFECTIOUS    DISEASES. 

PART  SIXTH. 

BACTERIA   IN    SURGICAL    LESIONS. 
BY    DR.  G.  M.   STERNBERG. 


PART    THIRD. 


TECHNOLOGY. 

OWING  to  their  minute  size  and  the  difficulties  at- 
tending their  study,  the  Bacteria  received  but 
little  attention  from  naturalists  prior  to  the  dis- 
covery by  Davaine  of  the  anthrax  bacillus  (Com- 
municated to  the  French  Academy  of  Sciences  in 
1863). 

Since  this  date,  very  great  progress  has  been 
made  in 'our  knowledge  of  these  minute  plants; 
and  this  progress  has  been  due,  to  a  consider- 
able extent,  to  the  labors  of  physicians  rather 
than  to  those  of  botanists,  who,  as  a  rule,  have 
been  inclined  to  make  light  of  the  importance 
attached  to  this  and  subsequent  discoveries  re- 
lating to  the  presence  of  parasitic  micro-organ- 
isms in  the  blood  or  tissues  of  man  and  the  lower 
animals  while  suffering  from  certain  infectious  dis- 
eases. We  are  greatly  indebted,  however,  to  the 
German  botanists,  Cohn  and  Nageli ;  and  to  the 
distinguished  French  chemist  Pasteur  must  be 
awarded  the  foremost  place  among  those  who  have 
contributed  to  our  knowledge  in  this  direction. 


156         TECHNOLOGY  OF  BACTERIA. 

As  in  other  branches  of  science,  progress  has  to 
a  great  extent  been  dependent  upon  improvements 
in  technique.  These  relate  especially  to  methods 
of  cultivation,  and  to  the  staining,  mounting  and 
photographing  of  bacterial  organisms. 

The  object  of  the  present  chapter  is  to  give  as 
concise  an  account  as  possible  of  the  technology 
as  at  present  perfected,  and  as  employed  by  the 
most  successful  modern  investigators. 

§  1.  —  METHODS  OF  CULTIVATION. 

For  the  solution  of  many  problems  relating  to 
the  life-histories  and  physiological  functions  of  the 
various  species  of  Bacteria,  it  is  essential  that 
a  "  pure  culture "  be  obtained  and  maintained 
through  successive  generations  by  the  inoculation 
of  fresh  portions  of  a  suitable  culture-medium. 
Evidently  this  requires  not  only  pure  stock  to 
commence  with,  but  also  a  culture-medium  free 
from  living  organisms  —  sterilized,  —  and  the  ex- 
clusion of  floating  atmospheric  germs. 

Methods  of  Obtaining  Pure  Stock. — Various  meth- 
ods have  been  devised  for  the  purpose  of  isolating 
a  single  species  when  mingled,  as  is  commonly  the 
case,  with  many  others.  Lister  proposed  to  ac- 
complish this  by  diluting  the  material  containing 
a  number  of  distinct  species  —  e.  g.  a  drop  of 
human  saliva  or  of  broken-down  beef  tea  which 
has  been  freely  exposed  to  the  air  —  with  a  steril- 


METHODS  OF  CULTIVATION.  157 

ized  fluid  until  there  shall  be  an  average  of  less 
than  one  living  germ  to  each  drop  of  fluid.  %If 
now  we  inoculate  numerous  separate  portions  of  a 
sterilized  culture-medium  with  a  single  drop,  each, 
of  this  diluted  stock,  it  is  evident  that  some  por- 
tions may  receive  no  living  seed,  others  may  have 
germs  of  two  or  more  species,  and  others  may 
chance  to  have  one  or  more  germs  of  a  single 
species.  In  the  latter  case,  the  multiplication  of 
these  germs  under  conditions  which  excluded  the 
possibility  of  contamination  from  without  would 
give  us  a  pure  culture  of  this  particular  species. 
So  far  as  the  writer  is  aware  this  method  has  not 
been  employed,  except  in  a  limited  number  of 
experiments  made  by  Lister  himself  in  order  to 
demonstrate  its  feasibility.  No  doubt  it  may  be 
successfully  employed,  but  it  would  involve  a 
great  expenditure  of  time,  and  success  would 
probably  be  the  exception  and  failure  the  rule, 
owing  to  the  difficulty  of  estimating  the  exact 
amount  of  dilution  required  in  the  first  instance, 
and  because  of  the  element  of  chance,  which  is  an 
essential  feature  of  the  method. 

The  same  result  is  accomplished  more  expedi- 
tiously  by  the  method  of  Koch,  the  essential  fea- 
ture of  which  consists  in  using  a  solid  sub-stratum 
as  the  culture-medium,  upon  which  the  mixed 
micro-organisms  are  distributed.  A  sufficient  quan- 
tity of  gelatine  (3  to  5  per  cent.)  is  added  to  a 
suitable  culture, -fluid  to  cause  the  mixture  to  jellify 
when  cooled.  While  still  warm,  this  gelatine  cul- 


158  TECHNOLOGY  OF  BACTERIA. 

ture-fluid  is  poured  upon  glass  slides,  to  which  it 
adheres  when  cool  in  the  form  of  a  semi-solid 
layer.  Upon  this  the  mixed  bacteria  are  dis- 
tributed by  means  of  a  needle,  the  point  of  which 
is  lightly  drawn  across  the  surface,  after  having 
been  charged  with  seed  by  dipping  it  into  the 
stock-solution  a  biological  analysis  of  which  is 
desired  —  e.  g.  broken-down  urine  or  beef  tea. 
The  different  micro-organisms  are  distributed  by 
this  method  along  the  track  of  the  needle,  and  the 
subsequent  multiplication  of  each  germ  in  situ, 
when  the  slide  has  been  left  for  a  day  or  two  in 
the  culture-oven,  produces  a  little  collection  of  the 
particular  species  to  which  it  belongs,  which  may 
be  recognized  under  the  microscope  or  even  by 
the  naked  eye. 

A  pure  culture  is  obtained  by  inoculating  a 
sterilized  culture-fluid  with  seed,  transferred  with 
due  precautions,  from  one  of  these  little  masses 
formed  along  the  track  of  the  needle. 

Another  method  which  suggests  itself,  and  will 
doubtless  be  found  useful  in  certain  cases,  depends 
upon  the  difference  as  to  reproductive  activity 
manifested  by  different  species  of  bacteria,  and 
upon  the  fact  that  a  culture-medium,  or  conditions 
as  to  temperature,  favorable  for  the  development 
of  one  species  may  not  be  for  another.  By  taking 
advantage  of  these  physiological  peculiarities  we 
may  succeed  in  excluding  all  but  a  single  form, 
by  one  or  more  culture  experiments,  notwithstand- 
ing the  fact  that  our  stock  was  impure  at  the 


METHODS  OF  CULTIVATION.  159 

outset.  It  is  evident  that  if  one  species  multiplies 
more  promptly  and  rapidly  than  the  others  which 
are  associated  with  it,  it  will  soon  be  present  in 
excess  in  a  culture-fluid  inoculated  with  the  com- 
mingled species,  and  that  by  using  this  stock  to 
start  a  second  culture  before  other  forms  have 
time  to  multiply,  repeating  the  operation  if  neces- 
sary through  a  series  of  cultures,  we  shall  at  last 
exclude  all  except  the  single  species  which  has 
taken  precedence  by  virtue  of  its  rapid  multipli- 
cation. 

In  the  same  way  we  may  take  advantage  of 
conditions  relating  to  the  composition  of  the  cul- 
ture medium,  and  to  the  temperature  at  which  it 
is  maintained  after  inoculation  with  impure  stock. 
When  the  conditions  are  most  favorable  for  the 
development  of  a  particular  species,  it  is  evident 
that  this  will  take  precedence  over  others  with 
which  it  is  associated.  And  it  may  happen  that 
conditions  extremely  favorable  for  one  are  entirely 
unsuited  for  other  species  which,  accordingly,  do 
not  multiply  at  all. 

We  have  examples  of  this  in  the  experiments 
which  have  been  made  upon  living  animals,  which 
may  be  considered  culture-experiments,  in  which 
the  blood  of  the  animal  serves  as  a  culture-fluid, 
and  in  which  the  temperature  maintained  is  neces- 
sarily that  of  the  species  used  in  the  experiment. 
Thus  in  the  form  of  septicaemia  in  the  mouse, 
which  has  been  studied  by  Koch,  a  drop  of  putrid 
blood  "  containing  bacteria  of  the  most  diverse 


160  TECHNOLOGY  OF  BACTERIA. 

forms  irregularly  mixed  together,"  injected  be- 
neath the  skin  of  the  animal,  gives  rise  to  an 
infective  disease  characterized  by,  and  dependent 
upon,  the  presence  of  a  multitude  of  minute  ba- 
cilli in  the  blood  and  tissues.  In  this  case,  it  is 
evident  that  the  conditions  are  favorable  for  the 
multiplication  of  this  species,  and  not  for  the 
others  associated  with  it  in  the  drop  of  putrid 
blood  introduced  into  the  living  culture-apparatus. 
This  experiment  enables  us  to  secure  a  pure  cul- 
ture of  this  particular  bacillus;  for  the  smallest 
quantity  of  blood  taken  from  the  vessels  of  the 
animal,  immediately  after  its  death,  contains  it  in 
abundance,  and  may  be  used  to  inoculate  a  steril- 
ized culture-fluid.  In  the  same  way,  if  we  inocu- 
late a  rabbit  with  a  drop  of  human  saliva,  which 
contains  a  variety  of  bacteria,  one  species  only 
multiplies  freely  and  invades  the  blood  of  the  ani- 
mal, producing  a  fatal  infectious  disease.  This  is 
a  micrococcus  of  oval  form  and  having  peculiar 
characters.  (Fig.  3,  Plate  VI.)  By  introducing  a 
little  of  the  blood  of  a  rabbit,  just  dead  as  the 
result  of  such  an  inoculation,  into  a  sterilized  cul- 
ture-fluid, we  obtain  a  pure-culture  of  this  micro- 
coccus,  which  may  be  maintained  indefinitely 
through  successive  generations  from  culture-tube 
to  culture-tube,  or  from  rabbit  to  rabbit,  thus  show- 
ing that  this  micrococcus  is  a  distinct  species,  as 
it  "breeds  true." 

Having   obtained   pure   stock   by   one    of    the 
methods  mentioned,  success  hi  cultivating  the  spe- 


METHODS  OF  CULTIVATION.  161 

cies  contained  in  it  will  depend  upon  the  use  of  a 
suitable  culture-medium,  and  the  maintenance  of 
favorable  conditions  as  to  temperature  and  a  suf- 
ficient supply  of  oxygen,  if  required. 

Natural  Culture-Fluids.  —  The  natural  culture- 
fluids  which  are  available  for  use  are  blood,  milk, 
urine,  and  aqueous  humor  from  the  eye  of  one  of 
the  lower  animals. 

All  of  these  have  been  used,  and  all  may  be 
obtained  in  a  pure  state  from  the  living  animal  by 
adopting  proper  precautions. 

Blood.  —  The  observations  of  numerous  experi- 
menters prove  that  the  circulating  fluid  in  healthy 
animals  is  free  from  all  bacterial  organisms.  To 
obtain  a  supply  for  experimental  purposes  it  must 
be  drawn  directly  from  the  vessels  into  a  sterilized 
receptacle.  This  may  be  accomplished  by  means 
of  a  glass  tube  drawn  out  at  each  end  to  form  a 
capillary  tube,  hermetically  sealed  at  each  extrem- 
ity and  thoroughly  sterilized  by  heat.  Such  a 
tube  is  to  be  filled  by  exposing  a  superficial  vein 
of  sufficient  size,  and  introducing  one  of  the  ca- 
pillary extremities  within  the  vessel  through  a 
very  small  orifice  made  through  its  walls.  The* 
end  of  the  tube  is  to  be  broken  off  within  the 
vessel,  after  which  the  outer  end  may  also  be 
broken,  to  allow  the  contained  air  to  escape  as  the 
tube  fills  with  blood.  This  will  not  be  necessary, 
however,  if  a  partial  vacuum  has  been  formed  by 

11 


162         TECHNOLOGY  OF  BACTERIA. 

sealing  the  capillary  extremities  in  the  flame  of  an 
alcohol  lamp  while  the  tube  was  still  quite  hot. 
Both  extremities  are  sealed  as  expeditiously  as 
'possible  as  soon  as  the  tube  is  withdrawn  from  the 
vessel.  It  is  evident  that  to  obtain  a  larger  quan- 
tity of  blood,  a  flask  having  two  necks  bent  at  a 
right  angle  and  drawn  out  to  form  capillary  tubes 
may  be  substituted  for  the  simple  straight  glass 
tube.  (See  Fig.  1.) 


Fig   1. 

The  color  of  the  blood,  due  to  the  presence  of 
the  red  corpuscles,  and  the  fact  that  these  ele- 
ments, after  a  time,  form  a  granular  debris  which 
might  interfere  with  the  recognition  of  minute 
micrococci,  are  objections  to  the  use  of  this 
fluid  in  culture  experiments.  Blood-serum,  how- 
ever, is  free  from  these  objections,  and  is  a  valua- 
ble culture-medium.  This  may  be  obtained  from 
a  flask,  like  that  shown  in  Fig.  1,  by  transferring 
the  serum,  after  it  has  separated  from  the  clot,  to 
"small  culture-flasks  like  those  described  on  page 
176  (Fig.  5),  by  the  method  there  detailed.  To 
accomplish  this,  one  of  the  arms  of  the  larger 
flask  is  broken  off  to  admit  the  capillary  extrem- 
ity of  the  smaller  one.  By  skilful  manipulation 
a  number  of  these  may  be  filled  with  transparent 


METHODS  OF   CULTIVATION.  163 

serum  with  but  little  chance  of  contamination  by 
floating  atmospheric  germs. 

Blood-serum  obtained  without  these  special  pre- 
cautions may  also  be  used  by  resorting  to  the 
method  of  Koch  for  sterilizing  it  subsequently  to 
its  separation  from  the  clot.  This  is  accomplished 
by  introducing  it  into  test-tubes  from  which  at- 
mospheric germs  are  excluded  by  a  plug  of  cotton, 
or  into  hermetically  sealed  culture-flasks,  like  those 
described  on  page  176,  and  exposing  it  for  an  hour 
daily  to  a  temperature  of  58°  C.  (136.4°  Fahr.)  for 
a  period  of  six  days.  This  method  insures  the  de- 
struction of  living  germs  contained  in  the  blood- 
serum  without  coagulating  the  albumen,  which 
would  destroy  its  value  as  a  culture-fluid.  If  a 
solid  culture-medium  is  desired,  the  blood-serum 
is  subsequently  subjected  to  a  temperature  of 
65°  C.  (149°  Fahr.)  for  several  hours.  A  solid, 
transparent,  jelly  is  produced  by  this  method, 
which  is  the  material  upon  which  Koch  cultivated 
the  tubercle  bacillus  in  his  experiments  relating  to 
tuberculosis. 

Milk.  —  The  experiments  of  Lister,  Roberts  and 
Cheyne  have  demonstrated  that  milk,  as  it  exists 
in  the  udder  of  the  cow,  is  free  from  the  germs 
of  fermentation  or  putrefaction,  and  may  be  pre- 
served indefinitely  without  undergoing  change,  if 
proper  precautions  are  taken  to  introduce  it  into 
sterilized  flasks  without  contamination  by  organ- 
isms detached  from  the  external  surface  of  the 


164         TECHNOLOGY  OF  BACTERIA. 

body  of  the  animal  or  by  floating  atmospheric 
germs.  It  is  difficult  to  accomplish  this,  however, 
and  in  practice  it  will  be  found  that  inilk,  although 
a  suitable  culture-fluid  for  various  organisms,  is  not 
commonly  available,  owing  to  the  difficulty  of  ob- 
taining it  from  its  source  free  from  contamination, 
and  to  the  fact  that  it  is  a  difficult  fluid  to 
sterilize. 

Urim.  —  Pasteur,  Lister,  the  present  writer,  and 
several  other  experimenters  have  succeeded  in 
obtaining  urine,  directly  from  the  bladder,  free 
from  bacterial  contamination,  and  which,  conse- 
quently, did  not  undergo  any  change  from  being 
kept,  although  exposed  freely  to  the  air — filtered 
—  and  to  a  temperature  suitable  for  inducing  the 
different  forms  of  fermentation  which  this  fluid 
undergoes  when  no  precautions  are  taken  to  ex- 
clude the  micro-organisms  to  which  these  changes 
are  due. 

In  man,  and  doubtless  in  the  lower  animals  also, 
the  orifice  of  the  urethral  canal  is  constantly  in- 
fested with  bacteria  of  different  species,  whereas 
the  deeper  portion  of  the  canal  and  the  bladder 
are  quite  free  from  them.  This  is  proved  by 
microscopical  examination,  and  by  the  fact  that 
urine  free  from  bacteria  may  be  obtained  by 
taking  the  precaution  to  destroy  those  located  in 
the  vicinity  of  the  meatus  urinarius  by  means  of 
a  suitable  disinfectant. 

The  writer  has  on  several  occasions  repeated 


METHODS   OF   CULTIVATION.  165 

with  success  the  experiment  of  Lister,  the  essen- 
tial feature  of  which  is  the  thorough  cleansing 
and  disinfection  of  the  urethral  canal  by  means 
of  a  solution  of  carbolic  acid  (5  per  cent).  The 
glans  should  also  be  washed  with  the  same  solu- 
tion ;  after  which  the  urine  is  passed  into  a  glass 
flask  or  test-tube  which  has  been  sterilized  by 
heat.  This  is  at  once  closed  with  a  plug  of 
cotton. 

Urine  has  been  extensively  used  as  a  culture- 
fluid,  and  is  well  suited  for  the  development  of 
many  species  of  bacteria;  and  especially  for  the 
micrococcus,  which  has  been  shown  by  Pasteur  to 
be  the  cause  of  the  alkaline  fermentation  which 
ordinarily  occurs  in  this  fluid  during  warm  weath- 
er, within  a  few  hours  after  its  escape  from  the 
bladder.  It  must  be  remembered,  however,  that 
decomposition  of  urea  into  carbonate  of  ammonia 
is  also  effected  by  heat,  and  that,  consequently, 
the  composition  and  reaction  of  this  fluid  is 
changed  by  boiling.  For  this  reason  its  sterili- 
zation by  heat  is  objectionable  for  certain  experi- 
ments, and  it  will  be  necessary  to  obtain  it  from 
the  bladder  free  from  bacterial  contamination,  by 
the  expedient  above  mentioned  (method  of  Lis- 
ter), or  by  means  of  a  sterilized  catheter  attached 
to  a  germ-proof  receptacle,  as  recommended  by 
Pasteur. 

Aqueous  humor,  obtained  from  the  eye  of  one  of 
the  lower  animals,  recently  dead,  is  a  sterile  albu- 


166         TECHNOLOGY  OF  BACTERIA. 

minous  fluid  which  has  been  utilized,  especially  by 
the  earlier  investigators,  as  a  culture-medium.  The 
method  of  operation  has  commonly  been  to  place 
a  drop  of  this  fluid,  obtained  from  the  eye  through 
a  sterilized  canula,  upon  a  perfectly  clean  cover- 
glass,  and  to  invert  this  over  a  shallow  glass  cell 
the  margin  of  which  has  been  wet  with  olive  oil, 
or  with  a  liquid  cement  of  some  kind.  This 
serves  to  attach  the  cover  and  to  exclude  atmos- 
pheric organisms.  The  drop  of  fluid  is  inoculated 
by  means  of  a  needle,  the  point  of  which  has  been 
dipped  into  the  stock-solution  containing  the  par- 
ticular organism  which  it  is  proposed  to  culti- 
vate. 

This  method  is  especially  useful  when  the  de- 
velopment of  an  organism  is  to  be  studied  by 
continuous  observation ;  for  the  slide  supporting  a 
culture-cell  made  in  this  way  may  be  placed  upon 
the  stage  of  the  microscope,  and  bacteria  in  the 
drop  of  fluid  may  be  observed  with  high  powers 
through  the  thin  glass  cover.  This  method  does 
not,  however,  offer  as  perfect  security  as  regards 
the  exclusion  of  extraneous  organisms  as  is  desira- 
ble, and  it  has  generally  been  abandoned  for  the 
methods  to  be  described  later,  in  which  a  consid- 
erable quantity  of  fluid,  enclosed  in  a  germ-proof 
receptacle,  is  used.  In  this  case  a  microscopical 
examination  of  .the  contained  organisms  requires 
that  a  small  portion  of  the  culture-fluid  be  with- 
drawn from  the  culture-flask,  and  continuous  ob- 
servation would  be  impracticable. 


METHODS   OF  CULTIVATION.  167 

Artificial  Culture- Fluids.  —  The  culture -fluids 
which  have  been  most  extensively  used  in  in- 
vestigations relating  to  the  physiology  and  life- 
histories  of  the  various  species  of  bacteria  are 
infusions  of  animal  and  vegetable  substances,  such 
as  beef,  mutton,  chicken,  fish,  gelatine,  turnip, 
potato,  cucumber,  hay,  malt,  etc.,  etc.  These  in- 
fusions, as  a  rule,  do  not  require  to  be  very  con- 
centrated, and  they  should  be  as  transparent  as 
possible,  as  the  slightest  opacity  from  suspended 
particles,  albuminoid  or  inorganic,  may  interfere 
with  the  detection  by  the  naked  eye  of  changes 
in  the  fluid  due  to  the  development  of  bacteria, 
and  with  the  recognition  of  these  organisms  upon 
microscopical  examination.  It  sometimes  occurs 
that  an  infusion  of  beef  or  of  chicken,  which  has 
been  carefully  filtered  and  is  quite  transparent, 
becomes  opalescent  from  the  coagulation  of  a 
minute  quantity  of  albuminoid  material  as  the 
result  of  the  operation  of  sterilization.  I  have 
found  this  opalescence  difficult  to  remove  by  fil- 
tration. It  is  objectionable,  but  could  hardly  be 
mistaken  for  the  opalescence,  or  milky  opacity, 
which  results  from  the  breaking-down  of  an  infu- 
sion of  this  kind,  and  with  due  care  the  experi- 
menter is  not  likely  to  be  deceived,  especially  if 
he  retains  a  portion  of  the  sterilized  fluid  for 
comparison  with  that  used  in  his  culture  experi- 
ments. 

Nitrogen,  which  is  an  essential  element  of  the 
protoplasm  of  bacterial  organisms,  is  supplied  by 


168         TECHNOLOGY  OF  BACTERIA. 

the  albumen  of  animal  or  vegetable  origin  which 
remains  in  solution  in  the  above-mentioned  cul- 
ture-media. But  this  element  can  also  be  appro- 
priated when  present  in  the  form  of  ammonia,  or 
of  one  of  the  salts  of  ammonia  in  combination 
with  a  vegetable  acid. 

Culture -fluids  may  therefore  be  made  which  are 
suitable  for  the  development  of  numerous  species 
of  bacteria,  by  adding  to  distilled  water  a  small 
quantity  of  a  salt  of  ammonia,  together  with  cer- 
tain mineral  salts,  as  in  the  formula  of  Mayer, 
given  on  page  113.  Pasteur's  solution  contains 
ten  per  cent,  of  sugar  candy  and  a  fraction  of  one 
per  cent,  of  ashes  of  yeast.  (See  p.  112.) 

Sterilization  of  Culture-Fluids. — Heat  is  the  agent 
most  available  for  the  sterilization  of  culture-fluids, 
as  chemical  reagents  which  would  accomplish  the 
same  result  would  also,  by  their  presence  in  the 
fluid,  prevent  the  development  of  organisms  intro- 
duced for  the  purpose  of  cultivation.  It  would 
doubtless  be  possible  to  sterilize  a  fluid  by  means 
of  a  chemical  reagent  —  a  mineral  acid  for  exam- 
ple— and  subsequently  to  neutralize  the  germicide 
agent  —  e.  g.  by  lime  or  magnesia.  But  in  prac- 
tice it  will  be  found  that  no  other  method  is  likely 
to  give  as  satisfactory  results  as  that  commonly 
employed ;  which  consists  in  subjecting  the  fluid, 
enclosed  in  a  germ-proof  receptacle,  to  a  tempera- 
ture which  insures  the  destruction  of  the  vitality 
of  contained  organisms. 


METHODS   OF  CULTIVATION.  169 

The  earlier  experimenters  assumed  that  a  boiling 
temperature  must  be  fatal  to  the  minute  organisms 
developed  in  organic  infusions;  and  this  false  as- 
sumption furnished  a  foundation  for  the  belief, 
entertained  by  some  of  them,  that  bacteria  might 
appear  in  such  fluids  by  heterogenesis.  The  as- 
sumption has  been  proved  to  be  false  by  the 
experiments  of  Pasteur,  of  Tyndall  and  of  many 
others,  and  it  is  now  known  that  the  reproductive 
spores,  of  endogenous  formation,  which  are  devel- 
oped in  certain  species,  may  resist  a  temperature 
considerably  above  the  boiling-point  of  water. 
(See  p.  119.)  The  writer,  while  conducting  a  se- 
ries of  experiments  in  the  biological  laboratory  of 
Johns  Hopkins  University,  during  the  summer 
of  1881,  was  greatly  troubled  by  the  fact  that  the 
laboratory  was  infected  by  the  spores  of  a  species 
of  bacillus,  which  developed  in  little  islands  on  the 
surface  of  his  culture-fluids,  even  when  they  had 
been  boiled  for  an  hour  or  more.  To  destroy  the 
spores  of  this  bacillus,  it  was  necessary  to  resort  to 
the  use  of  a  bath  of  paraffine,  or  of  concentrated 
salt-solution,  by  means  of  which  a  temperature  of 
105°  C.  was  secured.  This  temperature,  main- 
tained for  half  an  hour  to  an  hour,  proved  effec- 
tual in  the  destruction  of  these  ubiquitous  spores. 

Prolonged  boiling  will  doubtless  destroy  the  vi- 
tality of  the  most  refractory  spores ;  but  the  exact 
time  which  is  required  to  secure  success  in  every 
case  has  not  been  determined.  In  practice,  it  will 
be  found  best  to  keep  on  the  safe  side,  as  the  loss 


170  TECHNOLOGY  OF  BACTERIA. 

of  time  and  material  which  results  from  imperfect 
sterilization  is  annoying,  and  mistakes  may  arise 
from  a  false  confidence  in  the  success  of  the  opera- 
tion. To  avoid  these,  it  is  always  best  to  test 
culture-fluids  in  the  culture-oven  for  several 
days  before  using  them  for  any  experiment. 

The  maintenance  of  a  boiling  temperature  at 
intervals  for  a  day  or  two  is  more  effectual  than 
the  same  amount  of  continuous  boiling.  Pasteur 
has  shown  that  an  alkaline  fluid  is  more  difficult  to 
sterilize  than  one  having  an  acid  reaction.  The 
vitality  of  bacteria  in  active  growth  is  destroyed 
by  a  comparatively  low  temperature.  Thus  Chau- 
veau  has  recently  made  the  statement  (C.  E.  Ac. 
des  Sc.,  t.  XCIV.  p.  1694),  that  the  anthrax  bacil- 
lus is  killed  (in  blood)  by  exposure  for  nine  or  ten 
minutes  to  a  temperature  of  54°  (129.2°  Fahr.). 
According  to  Fnsch,  B.  termo  is  killed  by  a  tem- 
perature of  45°  to  50°  (113°  to  122°  Fahr.)  — time 
of  exposure  not  given.  The  writer  has  fixed  the 
thermal  death-point  of  the  micrococcus  of  induced 
septicaemia  in  the  rabbit  at  60°  (140°  Fahr.),  the 
time  of  exposure  being  ten  minutes;  that  of  Mi- 
crococcus ureae  was  found  to  be  the  same. 

The  method  adopted  by  Koch  for  the  ^teriliza- 
tion  of  blood-serum  for  his  experiments  with  the  tu- 
bercle bacillus  has  already  been  mentioned  (p.  163). 
This  method  depends  for  success  upon  the  fact  that 
the  temperature  employed,  58°,  is  sufficient  to  de- 
stroy growing  bacteria,  and  that  in  the  intervals 
between  the  daily  heating  for  one  hour  the  spores 


METHODS  OF  CULTIVATION.  171 

have  an  opportunity  to  germinate,  and  are  killed 
by  the  subsequent  heating.  The  writer  has  not 
been  successful  in  sterilizing  milk  by  this  method, 
and  has  recently  lost  the  greater  portion  of  a  batch 
of  tubes  containing  blood-serum,  carefully  treated 
according  to  Koch's  directions,  from  the  develop- 
ment of  Penicillium  glaiicum  upon  the  surface  of  the 
jellified  serum.  The  spores  of  this  fungus  were 
evidently  very  abundant  in  the  laboratory  at  the 
•  time  the  serum  was  introduced  into  these  tubes, 
which  had  been  well  sterilized  by  heat  and  were 
thoroughly  protected  by  cotton  wadding  tied  over 
the  mouth  of  each,  with  the  additional  precaution 
of  covering  this  with  a  piece  of  sheet-caoutchouc 
secured  by  a  rubber  band.  No  doubt  the  unusual 
abundance  of  the  spores  of  Penicillium  was  due  to 
the  disturbance  of  the  dust  upon  a  lot  of  books 
which  were  taken  down  from  an  upper  shelf  by 
my  assistants,  shortly  before  the  blood-serum  was 
decanted  and  introduced  into  the  culture- tubes. 
According  to  Pasteur,  the  spores  of  Penicillium 
and  other  common  mucedines  are  not  destroyed 
by  a  temperature  of  120  to  125°  C  (248-257°  F.), 
in  tlie  absence  of  moisture. 

Culture  Tubes  and  Flasks.  —  Glass  tubes  or  flasks 
are  iised  as  germ-proof  receptacles  for  the  steril- 
ized culture-fluids  mentioned.  Ordinary  test-tubes 
are  commonly  employed,  and  are  useful  for  many 
purposes.  They  should  be  thoroughly  heated  in 
an  oven,  or  in  the  flame  of  an  alcohol  lamp,  just 


172  TECHNOLOGY  OF  BACTERIA. 

before  the  fluid  is  introduced,  to  destroy  all  germs 
adhering  to  their  inner  surface.  The  culture-fluid 
may  be  sterilized  before  or  after  its  introduction 
into  these  tubes.  In  the  former  case,  the  opera- 
tion must  be  performed  expeditiously,  in  as  pure 
an  atmosphere  as  possible  ;  and  the  mouth  of  the 
tube  is  to  be  closed  at  once  with  a  plug  of  cotton- 
wool. It  is  evident  that  this  method  admits  of  the 
entrance  of  floating  atmospheric  germs  while  the 
tubes  are  being  filled,  and,  therefore,  that  a  certain 
proportion  are  likely  to  break  down.  The  per- 
centage of  failures  will  depend  upon  the  skill  of 
the  operator  and  upon  the  purity  of  the  atmos- 
phere in  which  the  operation  is  performed.  The 
liability  to  failure  from  contamination  by  floating 
germs  is  not,  however,  as  great  as  is  commonly 
imagined;  and  experience  proves  that  contact  with 
instruments  or  surfaces  —  e.  g.  the  lip  of  the  vessel 
from  which  the  culture-fluid  is  poured  —  which  are 
not  perfectly  pure,  is  a  more  frequent  cause  of  the 
breaking-down  of  the  culture-fluid. 

Sterilization  of  the  culture-fluid  after  its  intro- 
duction into  the  tubes,  offers  greater  security,  and 
the  following  method  of  manipulation  is  recom- 
mended :  Test-tubes,  or  wide-mouthed  bottles 
having  a  capacity  of  half  an  ounce  or  more,  are 
washed  clean,  and  the  mouth  of  each  is  covered 
with  several  layers  of  cotton-wadding.  This  is 
secured  in  position  by  means  of  a  strong  linen 
thread,  or  a  piece  of  copper  wire,  tied  about  the 
neck.  The  wide-mouthed  bottles  have  the  advan- 


METHODS  OF  CULTIVATION.  173 

tage  of  being  less  fragile,  and  of  standing  without 
support.  They  are  especially  useful  for  receiving 
a  solid  culture-medium,  such  as  gelatine  solution 
or  jellified  blood-serum,  as  the  surface  exposed  is 
greater  than  when  test-tubes  are  employed.  The 
only  disadvantage  attending  the  use  of  bottles  is 
their  liability  to  break  when  heated  in  a  water- 
bath  ;  but  this  will  not  happen  when  Koch's  meth- 
od of  sterilization  at  a  low  temperature.(140°  Fahr.) 
is  employed.  The  tubes,  or  wide-mouthed  bottles, 
are  next  placed  in  an  oven  and  subjected  for  an 
hour  or  more  to  as  high  a  temperature  as  the  cot- 
ton caps  will  bear  without  being  scorched  —  about 
300°  Fahr.  They  are  then  cooled,  and  the  culture- 
fluid  is  introduced,  without  removing  the  protec- 
tive cotton-cap,  through  a  little  funnel  having  a 
long  and  sharp-pointed  neck,  which  is  pushed 
through  the  layers  of  cotton-wadding,  either  di- 
rectly or  after  making  a  small  orifice  with  a  sharp- 
pointed  instrument.  Usually  but  one  or  two 
drachms  of  fluid  will  be  required  in  each  tube. 
This  must  be  sterilized  by  heat,  after  its  introduc- 
tion to  the  culture- tube,  unless  it  is  introduced 
directly  from  a  germ-proof  flask  with  a  slender 
neck,  such  as  the  writer  recommends  for  the  pres- 
ervation of  culture-fluids  in  bulk  (Fig.  5,  p.  177). 
In  this  case,  the  slender  neck  of  the  flask  is  passed 
through  the  flame  of  an  alcohol  lamp,  to  destroy 
germs  which  may  have  settled  upon  its  outer  sur- 
face ;  and  the  hermetically  sealed  extremity  is 
broken  off  with  forceps  which  have  also  been 


174 


TECHNOLOGY  OF  BACTERIA. 


recently  heated.  The  flask  is  then  inverted,  and 
the  capillary  neck  is  passed  through  the  opening 
in  the  protective  cap  of  a  culture-tube.  A  suf- 
ficient quantity  of  fluid  is  then  transferred  by  the 
application  of  gentle  heat  to  the  base  of  the  in- 
verted flask.  (See  Fig.  2.)  Care  must  be  taken 
not  to  wet  the  protective  cotton  with 
the  culture-fluid ;  and  immediately 
.  after  this  has  been  introduced,  the  ori- 
fice in  the  cotton  wadding  is  closed 
by  placing  two  more  layers  of  the 
same  material  over  those  which  had 
previously  been  secured  to  the  neck 
of  the  bottle  or  tube.  This  outer 
protective  layer  may  be  conveniently 
secured  in  position  by  means  of  a 
rubber  band  which  admits  of  its  be- 
ing quickly  removed  for  the  purpose 
Fig- 2>  of  introducing  the  bacteria  which  it 
is  proposed  to  cultivate,  or  of  extracting  a  drop  of 
fluid  for  microscopical  examination.  This  is  ac- 
complished by  means  of  a  capillary  tube  which  has 
been  sterilized  by  heat  just  before  it  is  used,  and 
which  is  introduced  through  the  small  opening  in 
the  inner  layers  of  the  cotton  cap.  When  tubes 
or  bottles  prepared  in  this  way  are  set  aside  for  a 
considerable  time,  or  when  the  free  admission  of 
oxygen  to  the  interior  is  not  considered  necessary, 
it  is  well  to  cover  the  cotton  cap  with  a  piece  of 
thin  sheet-caoutchouc,  secured  by  means  of  a  rub- 
ber band.  This  serves  to  protect  the  cotton  cap 


METHODS  OF  CULTIVATION.  175 

from  dust,  and  the  contained  fluid  is  less  liable  to 
contamination  when  the  outer  layer  of  cotton- 
wadding  is  removed  for  any  purpose.  It  is  well 
to  carbolize  the  cotton-wadding  used  for  the  outer 
protective  cap,  as  recommended  by  Lister.  This  is 
done  by  soaking  it  in  a  solution  of  one  part  of  crys- 
tallized carbolic  acid  in  one  hundred  parts  of  anhy- 
drous ether,  after  which  it  is  allowed  to  dry. 

Lister  has  shown  that  organic  infusions  may  be 
kept  indefinitely,  without  undergoing  change,  in  a 
wine-glass  covered  first  with  a  watch-glass,  and 
then  with  a  glass  shade  as  shown  in  Fig.  3.  The 
apparatus,  as  arranged  in  the  figure,  is  purified  by 
being  introduced  into  a  hot  oven ;  and  after  it  has 
cooled,  the  sterilized  fluid  is  introduced  from  a 
large,  double-necked  stock-bottle,  seen  in  Fig.  4. 
To  do  this,  the  cotton  cap  is  removed  from  the 
nozzle  of  the  stock-bottle,  and  the  half  of  a  rubber 
ball,  having  an  opening  in  the  centre,  is  attached  to 
its  extremity.  This  rubber  hemisphere,  which  has 
been  previously  sterilized  by  soaking  it  in  a  strong 
solution  of  carbolic  acid,  serves  the  purpose  of 
covering  the  mouth  of  the  wine-glass  when  the 
glass  cover  —  watch-glass  —  is  removed. 

Culture-Flasks  used  ly  the  Author.  —  The  writer 
described,  in  a  paper  read  at  the  meeting  of  the 
American  Association  for  the  Advancement  of 
Science,  in  August,  1881,  a  method  of  conducting 
culture-experiments  which  he  has  found  extremely 
satisfactory,  and  which  has  the  advantage  of  as- 


176 


TECHNOLOGY   OF  BACTERIA. 


Fig.  3. 

a,  wine-glass  ;  b,  glass  cover 
(watch-glass) ;  c,  bell-glass,  sup- 
ported by  a  square  glass  plate. 


suring  the  greatest  possible  security  from  contam- 
ination by  atmospheric  germs. 
The  culture-flasks  employed 
contain  from  one  to  four  fluid 
drachms.  "  They  are  made 
from  glass-tubing  of  three  or 
four  tenths  inch  diameter,  and 
those  which  the  writer  has 
used  in  his  numerous  experi- 
ments have  all  been  home- 
made. It  is  easier  to  make 
new  flasks  than  to  clean  old  ones,  and  they  are 
thrown  away  after  being  once  used.  Bellows,  op- 
erated by  the  foot,  and  a  flame  of  considerable  size 
—  gas  is  preferable  —  will  be  required  by  one  who 
proposes  to  construct  these  little  flasks  for  himself. 
After  a  little  practice,  they  are  rapidly  made ;  but 

as  a  large  number  are  re- 
quired, the  time  and  labor 
expended  in  their  prepara- 
tion is  no  slight  matter.  .  .  . 
After  blowing  a  bulb  at  the 
extremity  of  a  long  glass 
tube,  of  the  diameter  men- 
tioned, this  is  provided  with 
a  slender  neck,  drawn  out 
in  the  flame,  and  the  end  of 
Flg  4-  this  is  hermetically  sealed. 

(See  Fig.  5.)  Thus  one  little  flask  after  another 
is  made  from  the  same  piece  of  tubing,  until  this 
becomes  too  short  for  further  use. 


METHODS  OF  CULTIVATION.  177 

"  To  introduce  a  culture-liquid  into  one  of  these 
little  flasks,  heat  the  bulb  slightly,  break  off  the 
sealed  extremity  of  the  tube  and  plunge 
it  beneath  the  surface  of  the  liquid  (see 
Fig.  6).  The  quantity  which  enters  will 
of  course  depend  upon  the  heat  em- 
ployed, and  the  consequent  rarefaction 
of  the  enclosed  air.  Ordinarily  the  bulb 
is  filled  to  about  one  third  of  its  capacity 
with  the  culture-liquid,  leaving  it  two 
thirds  full  of  air,  for  the  use  of  the  micro- 
scopic plants  which  are  to  be  cultivated 
in  it. 

"  It  is  best  not  to  trust  to  the  sterilization  of  the 
culture-liquid  previously  to  its  introduction  into 
the  flasks ;  for,  however  great  the  precautions 
taken,  many  failures  would  be  sure  to  occur,  as 
the  result  of  contammation  by  atmospheric  germs 
during  the  time  occupied  in  the  manipulations. 
Sterilization  is  therefore  ef- 
fected by  heat  after  the  fluid 
has  been  introduced  and  the 
neck  of  the  flask  hermetically 
sealed  in  the  flame  of  an  alco- 
hol lamp. 

"  This  may  be  accomplished 
by   boiling  for  an  hour  in  a 
bath  of  paraffine  or  of  concen- 
trated salt  solution,  by  which  ng.8. 
a  temperature  considerably  above  that  of  boiling 

water  is  secured.     The  writer  is  in  the  habit  of 

12 


178         TECHNOLOGY  OF  BACTERIA. 

preparing  a  considerable  number  of  these  flasks  at 
one  time,  and  leaving  them,  in  a  suitable  vessel 
filled  with  water,  for  twenty-four  hours  or  longer 
upon  the  kitchen  stove.  Here  the  water-bath  is 
kept  boiling  at  intervals,  and  the  contents  of  the 
flasks  can  scarcely  fail  of  being  subjected  to  a  tem- 
perature of  212°  Fahr.  for  eight  or  ten  hours. 
When  the  time  is  less  than  this,  failures  in  sterili- 
zation are  likely  to  occur,  and  it  is  always  best  to 
keep  on  the  safe  side.  The  flasks  are  next  placed 
in  a  culture-oven  for  two  or  three  days,  at  a  tem- 
perature of  35  to  38°  (95  to  100°  Fahr.),  to  test 
the  success  of  the  previous  operation,  —  steriliza- 
tion. If  at  the  end  of  this  time  the  contents  re- 
main transparent,  and  no  film  —  mycoderma  —  has 
formed  upon  the  surface  of  the  liquid,  the  flasks 
may  be  put  aside  for  future  use,  and  can  be  pre- 
served indefinitely. 

"  To  inoculate  the  liquid  contained  in  one  of 
these  little  flasks  with  organisms  from  any  source, 
the  end  of  the  tube  is  first  heated,  to  destroy  germs 
attached  to  the  exterior  ;  the  extremity  is  then 
broken  off  with  sterilized  —  by  heat  —  forceps  ; 
the  bulb  is  very  gently  heated  so  as  to  force  out 
a  little  air ;  and  the  open  extremity  is  plunged 
into  the  liquid  containing  the  organism  to  be  cul- 
tivated. The  smallest  quantity  of  this  is  suffi- 
cient, and  as  soon  as  the  inoculation  is  effected, 
the  end  of  the  tube  is  again  sealed  in  the  flame 
of  an  alcohol  lamp.  A  little  experience  will  en- 
able the  operator  to  inoculate  one  tube  from  an- 


METHODS  OF  CULTIVATION.  179 

other;  to  introduce  a  minute  quantity  of  blood 
containing  organisms  directly  from  the  veins  of  a 
living  animal;  to  withdraw  a  small  quantity  of 
fluid  from  the  flask  for  microscopical  examination, 
etc.,  without  any  danger  of  contamination  by  at- 
mospheric germs."  1 

A  larger  flask  than  those  above  described,  hav- 
ing its  neck  drawn  out  in  the  same  way,  will  be 
found  the  most  satisfactory  receptacle  in  which 
to  preserve  a  quantity  of  stock  solution  from 
which  to  fill  the  smaller  flasks  as  required.  It  is 
well  not  to  attempt  to  preserve  too  great  a  quan- 
tity of  the  various  organic  infusions  used  in  ex- 
perimental work  of  this  kind,  in  a  single  flask; 
as  there  is  greater  danger  of  the  breaking  down, 
and  consequent  loss,  of  the  stock,  when  a  ves- 
sel is  frequently  opened  for  the  purpose  of 
withdrawing  a  portion  of  its  contents.  It  is  best 
therefore  to  use  a  number  of  flasks  of  moderate 
size,  rather  than  a  single  large  one.  There  is 
always  a  saving  of  time  and  labor,  when  extensive 
experiments  are  contemplated,  in  preparing  a 
considerable  quantity  of  the  various  culture-fluids 
at  one  time,  so  that  there  may  be  a  sufficient 
stock  on  hand  in  the  laboratory  to  enable  the 
experimenter  to  proceed  without  delay  with  any 
series  of  experiments  he  may  have  in  view.  The 
writer  keeps  constantly  on  hand  a  supply  of  the 
little  flasks  already  described,  charged  with  ster- 

1  Extract  from  a  paper  by  the  Author  on  "  The  Germicide  Value  of 
certain  Therapeutic  Agents."  The  American  Journal  of  the  Medical 
Sciences,  No.  CLXX.,  n.  a.,  pp.  321-343. 


180  TECHNOLOGY  OF  BACTERIA. 

ilized  urine,  beef- tea,  chicken  bouillon,  hay  infusion, 
Colm's  fluid,  etc.,  and  would  recommend  others  who 
may  be  inclined  to  pursue  experimental  investiga- 
tions relating  to  the  bacteria  to  provide  them- 
selves in  the  same  way.  For  a  reserved  supply 
of  these  and  other  culture-fluids,  flasks  containing 
from  two  to  four  fluid  ounces  will  be  found  of  a 
convenient  size.  The  necks  of  these  flasks  are  to 
be  drawn  out  in  a  powerful  flame,  so  as  to  form 
a  slender  tube  the  extremity  of  which  can  be 
easily  fused  in  the  flame  of  an  alcohol  lamp,  and 
which  is  long  enough  to  permit  of  its  being 
broken  off  at  the  end  and  resealed  several  times. 
The  fluid  is  introduced  into  these  flasks  exactly 
as  directed  for  the  smaller  ones,  viz.,  by  apply- 
ing heat  to  the  body  of  the  flask,  so  as  to  rarefy 
the  enclosed  air,  and  plunging  the  extremity  of 
the  slender  neck  of  the  flask,  inverted,  beneath 
the  surface  of  the  fluid  contained  in  a  suitable 
vessel.  These  flasks  are  to  be  hermetically  sealed 
and  sterilized  exactly  as  was  directed  for  the 
smaller  ones.  Each  flask  should  have  attached 
to  it  a  label  showing  the  character  of  its  contents 
and  the  date  of  sterilization. 

Culture-  Oven.  —  As  culture  experiments  are  com- 
monly conducted  at  a  constant  temperature,  it  is 
necessary  to  have  a  receptacle  for  the  culture- 
tubes  and  flasks  which  can  be  heated  artificially 
to  any  desired  point,  the  temperature  being  regu- 
lated by  a  thermostat. 


METHODS  OF  CULTIVATION.  181 

A  rectangular  copper  vessel,  having  double 
walls  to  contain  water,  enclosing  an  air-chamber, 
will  be  found  most  suitable  for  this  purpose.  When 
the  space  between  the  double  walls  is  filled,  the 
air-chamber  is  surrounded  with  water  on  all  sides, 
except  that  through  which  access  to  it  is  ob- 
tained. This  side  is  closed  by  a  swinging  or 
sliding  door.  If  the  oven  is  of  considerable  size, 
it  is  well  to  have  one  or  more  adjustable  shelves 
in  the  interior,  upon  which  tubes  and  flasks  may 
be  placed,  as  well  as  upon  the  floor.  A  suitable 
aperture  at  the  top  admits  the  thermostat  to  the 
water-bath,  and  another  aperture  serves  for  the 
introduction  of  more  water  when  required.  A 
third  aperture,  through  the  centre  of  the  upper 
side  of  the  oven,  leads  to  the  air-chamber,  and  ad- 
mits of  the  introduction  of  a  thermometer,  the  in- 
dex of  which  can  be  read  outside  while  the  bulb  is 
inside  of  the  oven.  In  a  well-equipped  laboratory 
several  of  these  culture-ovens  will  be  required,  as 
experiments  conducted  at  different  temperatures 
will  often  be  under  way  at  the  same  time. 

The  most  convenient  way  of  heating  an  oven 
of  this  kind  is  by  the  use  of  gas  and  of  a  Bunsen 
or  other  burner,  which  insures  the  complete  com- 
bustion of  the  carbon.  When  gas  is  used,  the 
thermostat  described  below,  well  known  in  chemi- 
cal laboratories,  may  be  employed. 

Thermostat  for  Gas  (Fig.  7).  —  The  elongated 
glass  bulb  a  contains  a  certain  quantity  of  mer- 


182 


TECHNOLOGY  OF  BACTERIA. 


cury  below,  and  air  above.  When  the  air  is  ex- 
panded by  heat,  the  mercury  rises  through  the 

tube  c,  which  passes 
through  the  perforated 
cork  d,  and  flows  into  the 
space  above  this  cork. 
The  tube  e  is  connected 
by  a  piece  of  rubber  tub- 
ing with  a  gas-jet,  and 
the  gas  continues  to  pass 
through  the  tube  f  to  the 
Bunsen  burner,  unless 
arrested  by  the  rising  of 
the  mercury,  which  acts 
as  a  valve  to  close  the 
lower  extremity  of  the 
tube  e.  This  tube  is  ad- 
justable through  the  cork 
j,  and  it  is  evident  that 
the  temperature  at  which 
Fi«- 7-  the  gas  supply  is  shut  off 

will  depend  upon  the  position  of  its  lower  extrem- 
ity. A  minute  aperture  in  the  side  of  the  tube 
e  permits  a  small  quantity  of  gasx  to  flow  to  the 
burner,  so  that  the  flame  may  not  be  entirely  ex- 
tinguished when  the  extremity  of  this  tube  is 
closed  by  the  rising  of  the  mercury.  There  is  dan- 
ger, however,  when  but  a  small  amount  of  gas  is 
admitted  to  a  Bunsen  burner  that  the  flame  may 
be  extinguished  by  currents  of  air.  It  will  there- 
fore be  found  best,  in  practice,  to  close  this  aper- 


METHODS  OF  CULTIVATION. 


183 


ture,  and  to  have  a  small  constant  jet  of  gas  at 
the  side  of  the  burner,  in  a  position  to  relight  the 
gas  coming  through  the  thermostat  to  the  burner 
when  the  valve  is  opened  by  the  falling  of  the 
mercury.  The  gas  for  this  side  jet  does  not  pass 
through  the  burner  or  the  thermostat. 

When  the  experimenter  is  so  situated  that  he 
cannot  obtain  a  supply  of  gas,  the  problem  of 
regulating  temperature  is  not 
quite  so  simple;  but  the  result 
may  be  accomplished  by  the  use 
of  a  magneto-electric  thermostat 
invented  by  the  writer  some  years 
since. 

The  regulating  thermometer, 
Fig.  8,  may  be  made  as  in  the 
thermostat  just  described;  but, 
instead  of  a  tube  conveying 
gas,  the  mercury,  when  it  rises 
through  the  tube  c  to  the  space 
above  the  cork  d,  meets  at  a  cer- 
tain point  —  adjustable  —  the  in- 
sulated  platinum  wires  e  and  /, 
completing  an  electric  circuit.  A 
constant  battery  is  required, — 
a  single  cup  is  sufficient,  —  and 
an  electro-magnet,  the  lever  of 
which  is  made,  by  some  simple 
contrivance,  to  cut  down  the  flame  of  the  kero- 
sene or  alcohol  lamp  used  as  a  source  of  heat. 

This    electro-magnetic    regulator   may  also   be 


a 


Fig.  8. 


184         TECHNOLOGY  OF  BACTERIA. 

used  with  gas,  when  great  accuracy  is  required, 
by  employing  the  valve  shown  in  Fig.  9,  which 

was  invented  by  the  writer 
for  this  purpose  several 
years  since. 

The  bent  tube  a  is  con- 
nected with  the  gas  supply 
by  a  piece  of  rubber  tubing. 
The  upright  arm  of  this  tube  is  enclosed  in  a  larger 
tube  by  having  an  outlet  e,  which  is  connected 
with  the  burner.  The  upper  end  of  this  larger 
tube  is  closed  by  means  of  a  piece  of  sheet-rubber, 
and  when  this  is  depressed  by  means  of  the  lever  c, 
the  flow  of  gas  through  the  valve  is  arrested.  The 
lever  c  has  attached  to  it  the  armature  d,  and  is 
operated  by  an  electro-magnet  under  the  control  of 
the  regulating  thermometer.  To  prevent  the  flame 
at  the  burner  from  being  entirely  extinguished 
every  time  the  valve  is  closed,  a  small  aperture  o 
is  made  in  the  upright  arm  of  the  bent  tube  a. 

§  2.  THE  EECOGNITION  OF  BACTERIA.  —  The 
breaking  down  of  a  culture-fluid,  either  as  the  re- 
sult of  inoculation  or  of  accidental  contamination, 
may  commonly  be  recognized  by  the  naked  eye. 
The  fluid,  previously  transparent,  may  become 
opalescent  or  milky  in  appearance,  from  the  pres- 
ence of  a  multitude  of  bacteria  distributed  through 
it ;  or  we  may  observe  a  pellicle  upon  the  surface, 
while  the  fluid  below  remains  transparent ;  or, 
if  some  time  has  elapsed,  the  micro-organisms, 


THE  RECOGNITION  OF  BACTERIA.      185 

having  exhausted  the  pabulum  necessary  for  their 
development,  may  have  settled  to  the  bottom, 
where  they  form  a  white  pulverulent  precipitate, 
while  the  fluid  above  is  transparent.  In  the  lat- 
ter case,  a  milky  appearance  is  produced  by  shak- 
ing the  tube  so  as  to  distribute  the  organisms 
throughout  the  fluid. 

There  is  usually  no  difficulty  in  recognizing,  by 
means  of  the  microscope,  the  minute  unicellular 
plants  to  which  this  change  in  our  culture-fluid  is 
due.  But  for  this  purpose  it  will  often  be  neces- 
sary to  use  comparatively  high  powers,  —  e.  g.,  a 
good  one- tenth  inch  objective,  —  and  to  resort 
to  the  use  of  staining  reagents.  For  information 
relating  to  the  optical  and  chemical  tests  by  which 
bacteria  are  to  be  distinguished  from  inorganic 
substances,  and  from  albuminous  or  fatty  granules, 
etc.,  the  reader  is  referred  to  Part  First  of  the 
present  volume,  which  treats  of  their  morphology, 
and  especially  to  the  remarks  in  the  second  chap- 
ter, pages  49-53. 

Motile  bacteria  are  at  once  recognized  as  living 
organisms ;  but  care  must  be  taken  not  to  mistake 
movement  due  to  currents  in  the  fluid,  or  the 
molecular  motion — brownien — which  minute  par- 
ticles undergo  when  suspended  in  a  fluid,  for  a 
vital  movement.  This  is  to  be  distinguished  by 
the  fact  that  the  movements  are  vibratory,  and  do 
not  result  in  a  change  in  the  location  or  relative 
position  of  the  moving  particles.  Bacteria  which 
have  exactly  the  same  refractive  index  as  the 


186         TECHNOLOGY  OF  BACTERIA. 

fluid  in  which  they  are  immersed,  are  invisible ; 
but  if  endowed  with  active  movement,  they  may 
be  detected  by  the  disturbance  they  cause  among 
motionless  objects  which  happen  to  lie  in  their 
course.  Thus  the  septic  vibrio  of  Pasteur  is  so 
slender  and  transparent  as  to  be  almost  invisible ; 
but  when  present  in  the  blood  of  a  septicaemic  rab- 
bit, its  vigorous  serpentine  movements  are  marked 
by  a  displacement  of  the  blood  globules,  which  it 
moves  as  a  serpent  moves  the  grass  in  which  it  is 
concealed.  This  septic  vibrio  I  have  found  in  the 
blood  of  rabbits,  victims  of  my  experiments  in 
New  Orleans  during  the  summer  of  1880. 

The  use  of  staining  reagents  is  indispensable 
for  the  recognition  of  these  extremely  transparent 
or  extremely  minute  species.  Their  value  has 
recently  been  demonstrated  by  Koch,  in  a  most 
striking  manner,  by  the  discovery  of  a  specific 
bacillus  in  the  lungs  and  sputum  of  patients  suf- 
fering with  pulmonary  consumption,  which  had 
escaped  the  observation  of  pathologists  and  mi- 
croscopists  up  to  the  time  of  his  announcement 
of  its  presence  and  peculiar  color-reaction. 

§  3.  STAINING  BACTERIA. — By  far  the  most  use- 
ful staining  reagents  are  the  aniline  dyes,  first  rec- 
ommended by  Weigert.  Previously  to  the  intro- 
duction of  this  method,  hasmatoxylin  had  been 
used  to  some  extent,  but  did  not  give  very  satis- 
factory results,  as  "  it  does  not  stain  rod-shaped 
bacteria  at  all,  and  only  colors  the  spherical  so 


STAINING  BACTERIA.  187 

slightly  as  to  prevent  their  certain  recognition 
when  isolated"  (Koch).  The  aniline  colors  most 
used  are  the  methyl- violet,  aniline-brown,  fuchsin, 
and  methyl-blue. 

An  aqueous  solution  of  methyl-violet  is  perhaps 
the  most  generally  useful  staining  fluid ;  and  in 
the  violet  ink  sold  by  the  stationers  we  have  a 
solution  ready  made,  which  answers  every  pur- 
pose. It  usually  requires  to  be  filtered.  The 
mode  of  operating  is  as  follows :  The  fluid  con- 
taining the  bacteria  to  be  stained  is  spread  in  as 
thin  a  layer  as  possible,  and  allowed  to  dry,  upon 
a  thin  glass  cover.  The  drying  may  be  hastened 
by  passing  the  cover-glass,  held  in  forceps,  through 
the  flame  of  an  alcohol  lamp.  A  drop  or  two  of 
the  staining-fluid  is  then  poured  upon  the  cover- 
glass,  and  after  being  left  a  short  time  is  washed 
away  by  a  gentle  stream  of  water,  or  by  agitating 
the  cover  in  a  glass  of  clean  water.  Usually  one 
or  two  minutes  is  sufficient  time  to  ensure  the 
staining  of  the  bacteria  attached  to  the  cover. 
For  immediate  examination,  it  is  now  only  neces- 
sary to  place  the  cover  on  a  glass  slide  over  a 
little  drop  of  distilled  water.  It  is  better,  how- 
ever, to  support  the  margin  of  the  cover  by  means 
of  a  circle  of  white  zinc  cement,  turned  in  the 
centre  of  the  slide.  This  prevents  the  bacteria 
from  being  detached  by  contact  with  the  slide.  If 
the  object  is  to  make  a  permanent  preparation,  a 
drop  of  some  preservative  fluid  is  placed  in  the 
shallow  cell  formed  by  the  circle  of  cement.  A 


188         TECHNOLOGY  OF  BACTERIA. 

saturated*  solution  of  acetate  of  potash,  or  a  weak 
solution  of  carbolic  acid  (one  per  cent),  or  camphor 
water,  may  be  used  for  this  purpose.  The  surplus 
fluid  is  removed  with  blotting  paper,  and  another 
circle  of  cement  is  turned  about  the  margin  of  the 
cover  to  hermetically  seal  the  cell.  Permanent 
preparations  may  also  be  made  by  mounting  in 
Canada  balsam.  In  this  case,  the  cover-glass  is 
allowed  to  dry  after  staining,  and  may  be  treated 
with  alcohol  and  oil  of  cloves,  although  this  is 
usually  unnecessary ;  and  too  long  an  exposure  to 
the  action  of  these  agents  is  likely  to  remove  the 
color  from  the  bacteria. 

To  demonstrate  the  presence  of  bacteria  in  the 
tissues,  the  following  method,  devised  by  Weigert, 
is  strongly  recommended  by  Koch  :  — 

"  The  objects  for  examination  are  first  hardened  in 
alcohol.  The  sections  made  from  these  are  allowed  to 
lie  for  a  considerable  time  in  a  pretty  strong  watery 
solution  of  methyl- violet.  They  are  then  treated  with 
dilute  acetic  acid,  the  water  removed  by  alcohol,  cleared 
up  in  oil  of  cloves,  and  mounted  in  Canada  balsam.  .  .  . 

"  This  is  of  course  only  a  general  outline  of  the 
method ;  for  the  individual  tissues,  and  more  especially 
the  different  forms  of  bacteria,  show  so  great  a  variety 
of  result  from  such  treatment  that  it  would  be  impos- 
sible to  lay  down  rules  which  would  be  universal  and 
which  would  apply  to  every  case.  For  many  objects 
fuchsin  is  best  adapted  ;  for  others  the  methyl  colors 
are  more  suitable.  Among  these  latter  there  exists 
such  a  difference  in  the  staining  power  that  the  sec- 
tions must  lie  in  one  solution  only  a  few  minutes,  in 
another  several  hours.  .  . 


STAINING  BACTERIA.  189 

"  The  strength  of  the  acetic  acid  solution  is  not  of 
much  consequence.  The  best  solution  is  one  contain- 
ing only  a  small  percentage  of  the  acid,  and  it  is  well 
not  to  allow  it  to  act  too  long.  The  other  manipula- 
tions, such  as  the  removal  of  water,  clearing  up,  and 
mounting,  are  exactly  the  same  as  in  the  preparation 
of  other  microscopic  specimens.  One  must  avoid  leav- 
ing the  sections  too  long  in  alcohol  or  oil  of  cloves; 
otherwise  the  staining  material  will  be  washed  out  by 
these  fluids."  l 

The  method  above  described  brings  to  view  the 
larger  forms  of  bacteria  which  may  be  distributed 
through  the  tissues ;  but,  according  to  Koch,  the 
smaller  forms  may  not  be  distinguished,  although 
deeply  stained,  and  require  for  their  demonstra- 
tion a  special  form  of  illuminating  apparatus, 
which  brings  out  the  "  color  picture/'  while  de- 
tails of  structure  are  to  a  great  extent  lost  (L  c. 
p.  27).  The  illuminating  apparatus  of  Abbe,  made 
by  Zeiss  of  Jena,  is  strongly  recommended  by  the 
author  quoted,  and  will  doubtless  be  found  an 
important  aid  in  difficult  investigations  of  the 
nature  indicated.  For  ordinary  work,  however, 
a  good  achromatic  condenser  will  furnish  the 
necessary  illumination,  and  it  will  be  found  that 
a  good  one-sixth  or  one-tenth  inch  objective  an- 
swers very  well  for  this  purpose. 

In  order  to  render  the  number  and  distribution 
of  the  bacteria  in  an  organ  more  evident,  Koch 

1  Traumatic  Infective  Diseases,  English  translation,  p.  23.  London, 
1880. 


190  TECHNOLOGY  OF  BACTERIA. 

recommends  the  following  method.  After  stain- 
ing with  an  aniline  color,  soak  the  sections  in  a 
weak  solution  of  carbonate  of  potash,  instead  of 
acetic  acid.  By  this  means  the  animal  tissues, 
including  nuclei  and  plasma  cells,  lose  their  color, 
while  the  bacteria  alone  remain  stained. . 

Staining  the  Tubercle- Bacillus.  —  The  following 
method  was  first  recommended  by  Koch:  One 
cubic  centimetre  of  a  concentrated  alcoholic  solu- 
tion of  methyl-blue  is  added  to  two  hundred 
cubic  centimetres  of  distilled  water,  and  well 
shaken ;  then  add,  under  continuous  shaking,  two 
tenths  cubic  centimetres  of  a  ten  per  cent  solution 
of  caustic  potash.  The  cover-glasses  upon  which 
tuberculous  sputum  has  been  spread  and  dried, 
or  thin  sections  of  a  tuberculous  lung,  etc.,  are 
left  in  this  solution  for  twenty -four  hours.  If  the 
solution  is  heated  in  a  water-bath  at  40°  C.,  the 
staining  will  be  effected  in  much  less  time,  —  half 
an  hour  to  an  hour.  The  preparation  is  next 
treated  with  a  concentrated  aqueous  solution  of 
visuvin,  which  should  be  filtered  just  before  it  is 
used.  After  one  or  two  minutes  this  is  washed 
off  with  distilled  water. 

The  visuvin  solution  discharges  the  blue  color 
from  the  cells,  nuclei  and  tissue  elements  gener- 
ally, giving  them  a  brown  color,  while  the  tuber- 
cle-bacilli retain  their  blue  color  and  are  readily 
recognized. 


STAINING  BACTERIA.  191 

Baumgarten' s  Method.  —  In  this  method  the  spu- 
tum dried  upon  a  cover-glass  is  moistened  with  a 
very  dilute  solution  of  potash,  —  one  or  two  drops 
of  a  thirty-three  per  cent  solution  in  a  small 
watch-glass  filled  with  distilled  water.  According 
to  Baumgarten  the  bacilli  may  now  be  seen  with 
a  power  of  400  to  500  diameters.  The  film  of 
sputum  is  then  allowed  to  dry,  and  the  cover- 
glass  is  passed  two  or  three  times  through  the  flame 
of  an  alcohol  lamp,  after  which  it  is  treated  with 
an  aqueous  solution  of  one  of  the  aniline  colors. 
Baumgarten  asserts  that  by  this  treatment  the 
decomposition  bacteria  are  deeply  colored,  while 
the  tubercle-bacilli  remain  absolutely  colorless. 

EhrlicJis  Method.  —  This  method  is  considered 
by  Koch  a  decided  improvement  upon  his  own, 
and  has  been  employed  with  success  by  numerous 
observers  in  various  parts  of  the  world,  especially 
for  the  examination  of  sputum.  This  is  spread 
upon  a  cover-glass  in  as  thin  a  layer  as  possible  ; 
and,  in  order  to  fix  the  albumen,  the  cover-glass 
is  passed  through  the  flame  of  a  lamp  three  or 
four  times,  or  kept  at  a  temperature  of  100  to 
110°  C.  for  an  hour.  The  staining  solution  is  pre- 
pared as  follows  :  About  five  parts  of  pure  aniline 
("  aniline  oil ")  are  added  to  one  hundred  parts  of 
distilled  water,  well  shaken,  and  filtered  through 
a  moistened  filter.  A  saturated  alcoholic  solution 
of  fuchsin,  methyl-violet,  or  gentian-violet,  is 
added  to  this  mixture,  drop  by  drop,  until  pre- 


192  TECHNOLOGY  OF7 BACTERIA. 

cipitation  commences.  The  cover-glass  is  allowed 
to  float  upon  this  mixture,  which  may  be  con- 
veniently prepared  in  a  watch-glass,  for  fifteen 
minutes  to  half  an  hour ;  the  side  upon  whicR 
the  sputum  has  been  spread  is,  of  course,  placed 
in  contact  with  the  staining  fluid.  The  cover  is 
then  washed  for  a  few  seconds  in  a  strong  solu- 
tion of  nitric  acid  (one  part  of  the  commercial 
acid  to  two  parts  of  distilled  water).  After  this 
it  must  be  thoroughly  washed  in  pure  water. 
By  this  process  the  stain  is  removed  from  every- 
thing but  the  tubercle  bacilli,  which  retain  the 
color  imparted  to  them  by  the  first  operation. 
The  ground-substance  may  now  be  stained  so  as 
to  give  a  strong  contrast  with  the  bacilli ;  brown 
if  the  bacilli  are  violet,  or  blue  if  they  have  been 
stained  red  with  fuchsin. 

Gibbs  Method.  —  The  following  method  of  stain- 
ing the  tubercle-bacillus  is  recommended  by  Dr. 
Gibbs,  of  King's  College,  London :  — 

"  The  great  advantage  consists  in  doing  away  with 
the  use  of  nitric  acid.  The  stain  is  made  as  follows  : 
Take  of  rosanilin  hydrochloride  two  grammes,  methyl 
blue  one  gramme  ;  'rub  them  up  in  a  glass  mortar.  Then 
dissolve  aniline  oil  3  c.  c.  in  rectified  spirit  15  c.  c. ;  add 
the  spirit  slowly  to  the  stains  until  all  is  dissolved,  then 
slowly  add  distilled  water  15  c.  c. ;  keep  in  a  stoppered 
bottle.  To  use  the  stain:  The  sputum  having  been 
dried  on  the  cover-glass  in  the  usual  manner,  a  few 
drops  of  the  stain  are  poured  into  a  test-tube  and 


STAGING  BACTERIA.  193 

warmed  ;  as  soon  as  steam  arises,  pour  into  a  watch- 
glass,  and  place*  the  caver-glass  on  the  stain.  Allow  it 
to  remain  for  four  or  five  minutes,  then  wash  in  methy- 
lated spirit  until  no  more  color  comes  away;  drain  thor- 
oughly and  dry,  either  in  the  air  or  over  a  spirit-lamp. 
Mount  in.  Canada  balsam.  The  whole  process,  after  the 
sputum  is  dried,  need  not  take  more  than  six  or  seven 
minutes.  This  process  is  also  valuable  for  sections  of 
tissue  containing  bacilli,  as  they  can  be  doubly  stained 
without  the  least  trouble.  I  have  not  tried  to  do  this 
against  time,  but  have  merely  placed  the  sections  in  the 
stain  and  allowed  them  to  remain  for  some  hours,  and 
then  transferred  them  to  methylated  spirit,  where  they 
have  been  left  as  long  as  the  color  came  out.  In  this 
way  beautiful  specimens  have  been  made,  without  the 
shrinking  which  always  occurs  in  the  nitric  acid  pro- 
cess." —  Lancet,  May  5,  1883. 

Cheyne  recommends  the  Weigert-Ehrlich  stain- 
ing solution.  The  formula  is  :  of  a  filtered  watery 
solution  of  aniline  one  hundred  parts,  of  a  satur- 
ated alcoholic  solution  of  the  basic  aniline  dye 
(methyl-violet,  gentian-violet,  fuchsin,  etc.,)  eleven 
parts ;  mix  and  filter.  Rapid  staining  is  obtained 
by  warming  the  solution.  The  specimens  are  then 
decolorized  by  immersion  in  nitric  acid  (one  part 
in  two  of  water),  and  stained  in  a  suitable  contrast 
color.  Very  delicate  sections  are  apt  to  be  injured 
by  immersion  in  the  nitric  acid."  Tn  this  case,  after 
staining  them  in  the  Weigert-Ehrlich  fuchsin  so- 
lution, they  may  be  washed  in  distilled  water,  im- 
mersed in  alcohol  for  a  moment,  and  then  placed 
in  the  following  contrast  stain  for  one  or  two 

13 


194         TECHNOLOGY  OF  BACTERIA. 

hours  :  distilled  water  100  c.  c.,  saturated  alcoholic 
solution  of  methyl  blue  20  ID.  c.,  formic  acid  10 
minims. 

According  to  Koch  the  bacillus  of  leprosy  has 
the  same  color  reaction  as  the  tubercle-bacillus, 
while  all  other  bacteria  known  to  him  differ  from 
these  in  that  the  color  imparted  by  one  of  the 
aniline  dyes  is  discharged  by  visuvin  and  by  nitric 
acid,  used  as  above  directed. 

The  tubercle-bacilli  stained  by  any  of  the  meth- 
ods given  are  likely  to  fade  after  a  time,  especially 
when  mounted  in  fluid,  e.  g.,  glycerine  or  water. 

§  4.  PHOTOGRAPHING  BACTERIA.  —  Bacteria  are 
prepared  for  photography  as  above  directed ;  that 
is,  a  thin  film  of  the  material  containing  them  is 
attached  to  a  cover-glass  by  drying,  stained,  and 
mounted  over  a  shallow  cell  containing  fluid,  or  in 
balsam.  For  the  larger  forms  methyl-violet  is  a 
suitable  stain  for  this  purpose;  but  a  color  less 
transparent  for  the  actinic  rays,  such  as  aniline- 
brown  or  visuvin,  will  be  required  for  the  smaller 
species. 

The  writer  has  given  an  account  of  the  technique 
of  photo-micrography  in  another  work,  to  which 
the  reader  desiring  fuller  information  is  referred.1 

It  is  but  fair  to  say  that  satisfactory  results  can 
only  be  obtained  by  the  expenditure  of  a  consid- 
erable amount  of  time  and  money,  as  the  work 

1  Photo-Micrographs  and  How  to  make  them.    James  R.  Osgood  & 
Co.,  Boston,  1883. 


PHOTOGRAPHING  BACTERIA.         195 

must  be  done  with  high  powers,  and  the  technical 
difficulties  to  be  overcome  are  by  no  means  incon- 
siderable. The  illustrations  in  the  present  volume 
may  be  taken  as  fair  samples  of  what  may  be  ac- 
complished, and  it  will  be  found  easier  to  criticise 
these  than  to  improve  upon  them.  Koch  says,  in 
his  "  Traumatic  Infective  Diseases  "  :  — 

"In  a  former  paper  I  expressed  the  wish  that  ob- 
servers would  photograph  pathogenic  bacteria,  in  order 
that  representations  of  tl\em  might  be  as  true  to  nature 
as  possible.  I  thus  felt  bound  to  photograph  the  bac- 
teria discovered  in  the  animal  tissues  in  traumatic  infec- 
tive diseases,  and  I  have  not  spared  trouble  in  the 
attempt.  The  smallest,  and  in  fact  the  most  interesting, 
bacteria,  however,  can  only  be  made  visible  in  animal 
tissues  by  staining  them,  and  by  thus  gaining  the  ad- 
vantage of  color.  But  in  this  case  the  photographer 
has  to  deal  with  the  same  difficulties  as  are  experienced 
in  photographing  colored  objects,  e.  g.,  colored  tapestry. 
These  have,  as  is  well  known,  been  overcome  by  the 
use  of  colored  collodion.  This  led  me  to  use  the  same 
method  for  photographing  stained  bacteria  ;  and  I  have 
in  fact  succeeded,  by  the  use  of  eosin-collodion,  and  by 
shutting  off  portions  of  the  spectrum  by  colored  glasses, 
in  obtaining  photographs  of  bacteria  which  had  been 
stained  with  blue  and  red  aniline  dyes.  Nevertheless, 
from  the  long  exposure  required  and  the  unavoidable 
vibrations  of  the  apparatus,  the  picture  does  not  have 
sharpness  of  outline  sufficient  to  enable  it  to  be  of  use 
as  a  substitute  for  a  drawing,  or  indeed  even  as  evi- 
dence of  what  one  sees.  For  the  present,  therefore, 
I  must  abstain  from  publishing  photographic  repre- 
sentations." 


196         TECHNOLOGY  OF  BACTERIA. 

The  difficulty  of  obtaining  satisfactory  photo- 
micrographs of  the  smallest  micro-organisms  is 
illustrated  in  Figures  3  and  6,  Plate  XL  These 
represent  the  best  results  which  the  writer  has 
been  able  to  attain  from  a  large  number  of  trials 
in  photographing  the  tubercle-bacillus.  In  Fig.  3 
there  are  six  of  these  bacilli,  included  within  an 
epitheloid  cell,  from  a  specimen  of  the  sputum  of 
a  tuberculous  patient.  The  specimen  is  well  stained 
with  fuchsin  by  Ehrlich's  method  ;  and  under  the 
microscope  the  outlines  of  the  cell,  with  its  nucleus 
and  the  deeply-stained  bacilli,  are  seen  very  dis- 
tinctly. But  in  the  attempt  to  photograph  this 
object  it  was  found  to  be  impossible  to  bring  all 
of  the  bacilli  into  focus  at  the  same  time ;  so  that, 
while  two  bacilli  are  seen  with  tolerable  distinct- 
ness, the  others,  being  a  little  out  of  focus,  can 
scarcely  be  distinguished.  Fig.  6  represents  the 
best  result  I  have  been  able  to  obtain  in  photo- 
graphing a  single  bacillus  from  the  same  source, 
stained  in  the  same  way,  —  with  fuchsin.  A  close 
inspection  will  show  that  this  bacillus  is  formed 
of  a  chain  of  four  oval  spores.  When  it  is  re- 
membered that  this  is  magnified  1,000  diameters, 
and  has  been  stained  and  mounted  secundum  artem, 
it  will  not  appear  surprising  that  this  minute  ba- 
cillus escaped  observation  for  so  long  a  time.1 

1  In  remodelling  the  plates  for  the  second  edition  of  this  work,  the 
photo-micrographs  above  referred  to  have  been  omitted,  and  we  give  in 
place  of  them  a  reproduction  of  some  of  Koch's  beautiful  illustrations 
(chromo-lithographs,  Plate  IX.),  which  will  no  doubt  be  found  more 
satisfactory. 


COLLECTION  OF  BACTERIA.  197 

§  5.  COLLECTION  OF  ATMOSPHERIC  BACTERIA.  — 
Fully  developed  bacteria  are  rarely  found  in  the 
atmosphere;  but  we  have  ample  evidence  that  the 
spores,  or  "  germs,"  of  numerous  species  are  con- 
stantly present,  in  association  with  the  reproductive 
elements  of  plants  higher  in  the  scale,  and  espe- 
cially of  the  Mucorini  and  other  microscopic  fungi. 

Considerable  attention  has  been  given  to  the 
study  of  atmospheric  organisms  with  reference  to 
the  question  of  their  possible  connection  with  the 
epidemic  prevalence  of  certain  diseases.  This  is 
not  a  proper  place  to  give  a  summary  of  the  results 
attained ;  but  the  general  statement  may  be  made, 
that  these  have  not  been  of  a  definite  character, 
and  that  up  to  the  present  time  no  one  has  suc- 
ceeded in  demonstrating,  in  infected  atmospheres, 
the  presence  of  any  specific  forms  of  bacteria 
which  were  clearly  connected  with  the  deleterious 
effects  produced  in  man  or  the  lower  animals  by 
the  respiration  of  such  atmospheres.  This  line  of 
investigation,  however,  has  by  no  means  been  ex- 
hausted ;  and  the  careful  and  systematic  study  of 
atmospheric  organisms  in  different  localities,  at 
different  seasons,  and  under  various  circumstances 
as  to  sanitary  conditions,  is  greatly  to  be  desired. 
Any  one  who  may  be  inclined  to  enter  this  field 
of  investigation  will  do  well  to  make  himself 
familiar  with  what  has  already  been  done,  and 
especially  with  the  work  of  Maddox  and  Cunning- 
ham of  England,  and  of  Miquel  of  Paris.  The 
last-named  observer  has  given  much  time  to  the 


198         TECHNOLOGY  OF  BACTERIA. 

enumeration  of  atmospheric  bacteria.  He  finds, 
as  might  have  been  expected,  that  they  are  more 
abundant  during  the  summer  months;  and  that 
they  are  less  numerous  immediately  after  a  heavy 
rain,  which  has  the  effect  of  purifying  the  atmos- 
phere, by  washing  out  suspended  particles. 

Kain-water  will  always  be  found  fertile  in  germs  ; 
and  it  is  evident  that  when  collected  with  care  it 
represents  the  bacterial  flora  of  the  atmosphere  at 
the  time  of  its  fall.  We  may  therefore  study  this 
by  means  of  culture-experiments,  in  which  a  variety 
of  sterilized  organic  infusions  are  inoculated  with 
one  or  more  drops  of  rain-water  which  has  just 
fallen.  It  is  necessary  to  use  many  different 
culture-fluids,  because  various  organisms  require 
special  media  for  their  development. 

Again,  we  may  expose  our  sterilized  organic  in- 
fusions to  the  air,  and  thus  permit  them  to  become 
fertilized  by  the  deposition  of  air-borne  germs,  the 
development  of  which  is  subsequently  studied  as 
they  germinate  upon  the  surface,  or  in  the  interior, 
of  these  infusions. 

Solid  culture-media  are  especially  useful  for  this 
mode  of  investigation,  and  we  may  employ  organic 
infusions  to  which  three  to  five  per  cent  of  gelatine 
has  been  added,  as  recommended  by  Koch ;  and 
also  a  variety  of  cooked  alimentary  substances, 
such  as  moist  bread,  slices  of  boiled  potato,  turnip, 
onion,  etc.,  various  fruits  (cooked  or  uncooked), 
meats  of  different  kinds,  etc.  Upon  the  surface 
of  these,  if  they  are  kept  moist,  and  are  placed  in 


COLLECTION  OF  ATMOSPHERIC  BACTERIA.       199 

a  culture -oven,  maintained  at  a  suitable  tempera- 
ture, little  colonies  of  various  organisms  will  form 
from  the  germination  of  spores  deposited  from  the 
atmosphere.  These  will  soon  be  recognized  by  the 
naked  eye,  and  different  species  may  often  be  dis- 
tinguished by  peculiarities  as  to  growth,  color,  etc. 
It  must  be  remembered  that  the  microbes  found 
in  the  atmosphere,  so  far  as  we  now  know,  are 
accidentally  present,  and  have  originated  else- 
where; i.  e.y  in  decomposing  material  of  organic 
origin  from  the  surface  of  the  earth.  But,  while 
we  have  no  evidence  that  any  known  species  finds 
the  pabulum  necessary  for  its  development  in  the 
atmosphere,  yet  there  is  nothing  improbable  in 
the  supposition  that  this  may  be  true,  and  that 
there  are  species  of  bacteria  which  find  in  the  at- 
mosphere all  of  the  conditions  necessary  for  their 
rapid  multiplication.  We  know  that  plants  much 
higher  in  the  scale,  which  are  merely  attached  to 
others  for  support,  —  epiphytes, —  derive  their  sus- 
tenance directly  from  the  atmosphere ;  and  it  is 
easy  to  believe  that,  under  exceptional  circum- 
stances as  to  the  presence  of  organic  matter  and 
moisture,  especially  in  tropical  climates,  or  during 
the  summer  months  in  more  northern  latitudes, 
some  of  these  minute  microscopic  plants  may  also 
multiply  abundantly  while  suspended  in  the  atmos- 
phere. 

To  judge  of  the  relative  abundance  of  special 
forms  of  bacteria  in  the  atmosphere,  it  will  be 
necessary  to  resort  to  direct  microscopic  examina- 


200         TECHNOLOGY  OF  BACTERIA. 

tion  of  the  dust  deposited  upon  exposed  surfaces, 
or  of  the  suspended  particles  collected  by  means 
of  an  aeroscope. 

Various  forms  of  aeroscope  have  been  devised, 
the  object  of  all  being  to  cause  a  current  of  air  to 
pass  through  a  small  aperture  against  a  glass  slide, 
the  centre  of  which  has  been  smeared  with  glycer- 
ine or  some  other  viscid  material,  which  serves  to 
retain  suspended  particles.  In  the  apparatus  of 
Maddox,  which  was  used  by  Cunningham  in  India, 
and  a  modification  of  which  is  employed  by  Miquel, 
a  metal  cone  is  made  to  face  the  wind  by  means 
of  a  weather-vane  to  which  it  is  attached.  A  small 
aperture  at  the  apex  of  the  cone  permits  the  con- 
centrated current  of  air  to  project  itself  against 
a  glass  slide,  smeared  with  glycerine,  which  is 
properly  supported  at  a  short  distance  back  of  this 
orifice.  In  the  apparatus  used  by  Klebs  and 
Tomasi-Crudeli,  in  their  investigations  in  the  vicin- 
ity of  Rome,  a  current  of  air  is  produced  by  a 
revolving  "  fan-wheel "  moved  by  clock-work.  The 
writer,  in  his  investigations  in  Havana  in  1879, 
and  in  New  Orleans  in  1880,  used  a  water-aspirator, 
by  means  of  which  a  measured  quantity  of  air  was 
caused  to  flow  in  a  given  time,  through  a  small 
aperture,  and  to  impinge  upon  a  glass  slide  smeared 
with  glycerine.  Any  one  of  these  methods  will 
answer  the  purpose  ;  but  the  apparatus  of  Maddox 
seems  to  be  the  simplest,  and  has  yielded  very 
satisfactory  results. 

Instead  of  collecting  the  suspended  organisms 


ATTENUATION  OF  VIRUS.  201 

by  means  of  a  drop  of  glycerine  attached  to  a 
glass  slide,  Pasteur  has  proposed  to  collect  them 
by  passing  a  current  of  air  through  a  glass  tube 
containing  a  loosely-packed  filter  of  gun-cotton. 
This  is  subsequently  dissolved  in  ether,  and,  upon 
evaporation  of  the  ether,  the  particulate  atmos- 
pheric impurities  are  found  in  the  film  of  collodion 
remaining. 

Examination  of  Water.  —  The  bacterial  flora  of 
water  from  any  source  may  be  studied  by  the 
method  already  referred  to  in  speaking  of  rain- 
water ;  viz.,  by  using  a  small  quantity  to  inoculate 
a  variety  of  sterilized  organic  infusions,  and  ob- 
serving the  development  of  the  various  micro- 
organisms which  make  their  appearance  as  the 
result  of  this  procedure. 

Dr.  Angus  Smith  of  Manchester  has  recently 
given  a  favorable  account  of  results  obtained  by 
the  gelatine  method  proposed  by  Koch.  Pure  fish- 
gelatine  is  added  to  the  water  to  be  tested,  in 
sufficient  quantity  to  form  a  gelatinous  mass.  If 
the  water  is  pure,  this  remains  for  a  long  time  un- 
altered ;  but,  if  impure  from  the  presence  of  living 
organisms,  the  gelatine  becomes  liquefied  in  the 
vicinity  of  these,  and  little  bubbles  are  formed,  at 
the  bottom  of  which  the  bacteria  will  be  found. 

§  6.  ATTENUATION  OF  VIRUS. — Various  methods 
of  producing  physiological  varieties  of  pathogenic 
bacteria,  to  be  used  in  protective  inoculations,  have 


202  TECHNOLOGY  OF  BACTERIA. 

been  proposed  since  Pasteur  first  announced  (1880) 
that  the  microbe  of  fowl-cholera  could  be  modified, 
by  special  treatment,  in  such  a  manner  that  it  no 
longer  produced  a  fatal  form  of  the  disease ;  and 
that  fowls  inoculated  with  this  "  attenuated  virus  " 
were  subsequently  protected  against  the  disease, 
resisting  inoculation  with  the  most  potent  virus. 

Method  of  Pasteur.  —  Pasteur  found  that  the 
poison  of  fowl-cholera  was  most  virulent  when  ob- 
tained from  fowls  which  had  died  from  a  chronic 
form  of  the  disease,  and  that  this  virus  could  be 
cultivated  in  chicken-bouillon  for  many  successive 
generations  without  any  diminution  of  its  potency, 
if  the  interval  between  two  successive  inoculations 
was  not  greater  than  two  months.  But  when  a 
greater  interval  than  this  was  allowed  to  elapse, 
the  disease  produced  by  inoculation  was  of  a  less 
serious  character,  and  fewer  deaths  occurred.  This 
diminution  of  virulence  became  more  marked  in 
proportion  to  the  length  of  time  during  which  a 
culture-solution  containing  the  microbe  remained 
exposed  to  the  action  of  the  atmosphere,  and  at 
last  all  virulence  was  lost,  as  a  result  of  the  death 
of  the  parasite.  That  this  result  is  due  to  contact 
with  the  oxygen  of  the  air  is  shown  by  the  fact 
that  virus  enclosed  in  sealed  tubes  does  not  undergo 
this  modification,  but  retains  its  full  virulence  for 
many  months.  According  to  Pasteur,  the  various 
degrees  of  modification  of  virulence  produced  by 
prolonged  exposure  to  oxygen  are  preserved  by 


ATTENUATION  OF  VIRUS.  203 

the  cultivation,  at  short  intervals,  of  the  different 
grades  of  "  attenuated  virus." 

Subsequent  experiments  with  the  virus  of  an- 
thrax (charbon)  gave  similar  results ;  and,  under  the 
direction  of  Pasjieur,  extensive  protective  inocula- 
tions have  been  practised  in  France  with  attenu- 
ated virus  prepared  by  this  method. 

The  time  of  exposure  to  oxygen  is  less  for  the 
anthrax  bacillus  than  is  required  in  the  case  of  the 
micrococcus  of  fowl-cholera ;  and  it  is  necessary 
to  cultivate  the  bacillus  in  such  a  way  as  to  pre- 
vent the  development  of  spores,  as  these  retain 
their  virulence  unchanged  for  many  years.  This 
is  accomplished  by  cultivating  the  bacillus  at  a 
temperature  of  42°  to  43°  C.,  at  which  point  no 
spores  are  developed,  the  organism  multiplying  by 
fission  only.  Contact  with  the  atmosphere  for  a 
month  destroys  entirely  the  vitality  of  the  bacillus 
in  such  a  culture,  and  in  eight  days  it  loses  its 
deadly  properties, — the  temperature  being  main- 
tained at  the  point  mentioned.  During  this  time 
the  virus  passes  through  successive  degrees  of  at- 
tenuation. It  is  possible  to  restore  the  mitigated 
virus  to  its  full  activity  by  inoculating  a  guinea- 
pig  one  day  old^  which  is  killed  by  the  operation, 
and  using  the  blood  of  this  animal  to  inoculate  a 
second ;  and  so  on.  After  repeating  this  operation 
several  times,  the  poison  is  said  by  Pasteur  to  re- 
gain its  full  vigor,  and  to  be  fatal  to  a  sheep.  In 
the  same  way  the  attenuated  virus  of  fowl-cholera 
may  be  restored  to  full  vigor  by  inoculating  a 


204         TECHNOLOGY  OF  BACTERIA. 

small  bird,  —  sparrow  or  canary,  —  to  which  it  is 
fatal.  After  several  successive  inoculations  from 
bird  to  bird,  the  virus  resumes  its  original  activity. 

Method  of  Toussaint.  —  The  effect  produced  upon 
pathogenic  organisms  by  prolonged  exposure  to 
oxygen,  Toussaint  proposes  to  produce  more  ex- 
peditiously,  by  subjecting  them  for  a  short  time  to 
a  temperature  a  little  less  than  is  required  for  the 
complete  destruction  of  vitality. 

According  to  Chauveau,  this  is  best  accomplished, 
in  the  case  of  Bacillus  anthrads,  by  exposure  for 
eighteen  minutes  to  a  temperature  of  50°  C.  Ex- 
posure to  this  temperature  for  twenty  minutes  is 
said  to  kill  the  bacillus ;  while  "  heating  for  eighteen 
minutes  produces  an  excellent  attenuated  virus  for 
vaccination." 

A  first  vaccination  with  feeble  virus  (heated  to 
50°  for  fifteen  minutes),  and  a  second  inoculation, 
at  the  end  of  fifteen  days,  with  a  strong  virus  (blood 
heated  to  50°  for  nine  or  ten  minutes),  preserves 
sheep  from  the  effects  of  subsequent  inoculations 
with  virus  of  full  strength.  The  heating  must  be 
in  small  tubes,  not  more  than  1  mm.  in  diameter ; 
and  at  the  end  of  the  time  fixed  these  must  be 
quickly  withdrawn  from  the  hot  bath  and  plunged 
into  cold  water. 

The  blood  of  a  guinea-pig  which  has  just  died 
from  anthrax,  at  the  end  of  thirty-six  to  forty-eight 
hours  from  the  time  of  inoculation,  is  said  to  be  a 
good  active  virus  upon  which  to  operate  by  this 


ATTENUATION  OF  VIKUS.  205 

method.  The  attenuated  virus,  when  used  to  in- 
oculate a  culture-fluid,  develops  more  or  less 
rapidly,  according  to  the  degree  of  attenuation. 
Bacilli  heated  for  the  longest  time,  and  those  sub- 
jected to  the  highest  temperature,  are  the  longest 
in  showing  signs  of  development. 

MetJwd  of  CJiauveau.  —  Chauveau  has  attempted 
to  test  experimentally  the  question  whether  sus- 
ceptible animals  might  not  resist  infection  by  a 
small  number  of  active  bacilli,  and  acquire  im- 
munity as  the  result  of  such  inoculation.  His 
results  were  favorable  to  the  view  that  this  is  true 
as  regards  anthrax,  at  least ;  and  Salmon  has  since 
adduced  satisfactory  evidence  that  it  also  applies 
to  fowl-cholera.  The  method  adopted  by  Chau- 
veau consisted  in  diluting  infected  blood  from  the 
guinea-pig  until  a  cubic  centimetre  of  the  mixture 
contains,  as  nearly  as  can  be  computed,  the  num- 
ber of  bacilli  desired.  A  given  quantity  of  this 
fluid  was  injected  into  the  jugular  vein  of  a  sheep. 
Sheep  of  native  French  breeds  were  invariably 
killed  when  the  number  of  bacilli  introduced  into 
the  circulation  was  about  one  thousand.  In  an 
experiment  in  which  two  hundred  and  fifty  bacilli 
were  injected  into  each  of  five  sheep,  all  with- 
stood the  dose,  and  four  showed  immunity  when 
reinoculated  at  the  end  of  six  weeks.  Immunity 
against  symptomatic  anthrax  was  also  procured  by 
the  same  procedure.  Salmon,  who  has  tested  this 
method  in  fowl-cholera,  has  arrived  at  the  follow- 
ing conclusions  :  — 


206         TECHNOLOGY  OF  BACTERIA. 

"  First.  —  A  single  disease-germ  cannot  produce  this 
extremely  virulent  disease ;  it  cannot  even  multiply 
sufficiently  to  produce  the  local  irritation  at  the  point 
of  inoculation.  When  a  quantity  of  virus  was  intro- 
duced into  the  tissues,  which  should  have  contained  at 
least  twelve  germs,  there  was  no  effect,  either  general 
or  local ;  but  by  increasing  this  one  third,  with  the  same 
birds,  the  local  irritation  appeared. 

"  Second.  —  It  is  apparent  that  the  local  resistance  to 
the  germs  fails,  while  the  constitutional  resistance  may 
still  be  perfect,  and  that  in  this  case  there  may  be  a 
local  multiplication  of  the  organisms  for  two  or  three 
weeks  without  any  disturbance  of  the  general  health. 

"  Third.  —  That  this  local  multiplication  of  the  virus 
is  sufficient  to  grant  a  very  complete  immunity  from  the 
effects  of  such  virus  in  the  future." 1 

Method  by  Intravenous  Injection.  —  In  sympto- 
matic anthrax,  it  has  been  found  by  Arloing, 
Cornevin,  and  Thomas,  that  intravenous  injection 
of  the  virus  produces  in  the  calf,  the  sheep,  and  the 
goat  only  a  slight  indisposition,  lasting  for  two  or 
three  days;  and  that  subsequently  the  tumors 
characteristic  of  this  disease  are  not  developed  as 
the  result  of  inoculation  in  the  muscles  with  the 
bacterium  to  which  the  disease  is  ascribed. 

Attenuation  of  Virus  ly  Chemical  Reagents.  —  The 
attenuation  of  virulence  which  results  from  ex- 
posure to  oxygen  (method  of  Pasteur),  or  to  an 
elevated  temperature  (method  of  Toussaint),  seems 
to  depend  upon  diminished  reproductive  activity 

i  The  Med.  Record,  April  7,  1833,  p.  371. 


ATTENUATION  OF  VIRUS.  207 

of  the  pathogenic  organism.  Evidently  the  tis- 
sues of  a  susceptible  animal  are  able  to  resist  the 
invasion  of  a  limited  number  of  active  germs  (di- 
lution of  virus),  and  of  a  still  greater  number  of 
those  which  are  less  active  as  a  result  of  the 
treatment  referred  to. 

The  writer  has  obtained  evidence,  in  the  course 
of  his  experiments  relating  to  the  comparative 
value  of  disinfectants,  which  goes  to  show  that 
certain  chemical  reagents,  also,  may  modify  the 
virulence  of  pathogenic  bacteria  in  a  similar  man- 
ner. In  these  experiments,  the  blood  of  a  rabbit 
recently  dead  from  induced  septicaemia  was  the 
virulent  fluid  used  as  a  test.  The  pathogenic  or- 
ganism in  this  case  is  a  micrococcus,  which  is 
found  in  normal  human  saliva.  In  the  published 
report  of  these  experiments  the  following  state- 
ment is  made :  — 

"  The  most  important  source  of  error,  however,  and 
one  which  must  be  kept  in  view  in  future  experiments, 
is  the  fact  that  a  protective  influence  has  been  shown  to 
result  from  the  injection  of  virus,  the  virulence  of  which 
has  been  modified,  without  being  entirely  destroyed,  by 
the  agent  used  as  a  disinfectant."  l 

Sodium  hyposulphite  and  alcohol  were  the  chem- 
ical reagents  which  produced  the  result  noted  in 
these  experiments ;  but  it  seems  probable  that  a 
variety  of  antiseptic  substances  will  be  found  to 
be  equally  effective,  when  used  in  the  proper  pro- 

1  Studies  from  the  Biological  Laboratory,  Johns  Hopkins  University, 
Vol.  II.  No.  2,  p.  205. 


208  TECHNOLOGY  OF  BACTERIA. 

portion.  Subsequent  experiments  have  shown  that 
neither  of  these  agents  is  capable  of  destroying 
the  vitality  of  the  septic  micrococcus  in  the  pro- 
portion used  (one  per  cent  of  sodium  hyposulphite 
and  one  part  of  ninety-five  per  cent  alcohol  to 
three  parts  of  virus),  and  that  both  have  a  re- 
straining influence  upon  the  development  of  this 
organism  in  culture-fluids. 


PAET  FOURTH. 


GERMICIDES  AND  ANTISEPTICS. 

A  KNOWLEDGE  of  the  vital  resistance  of  the 
various  species  of  bacteria  to  the  action  of  differ- 
ent chemical  reagents  is  important  from  several 
points  of  view.  First,  such  information  has  an 
important  bearing  upon  elementary  biological 
problems,  which  are  best  studied  in  these  simple 
unicellular  plants;  second,  practical  sanitation,  and 
the  preservation  of  various  food-products,  depend 
to  a  considerable  extent  upon  the  proper  use  of 
germicides  and  antiseptic's;  and,  third,  modern 
therapeutics  has  been  largely  influenced  by  the 
indications  which  this  knowledge  seems  to  furnish 
for  the  treatment  of  infectious  diseases  and  surgi- 
cal injuries. 

By  a  germicide  agent  we  mean  one  which  has 
the  power  to  destroy  the  vitality  of  the  various 
species  of  bacteria  known  to  us,  including  those 
disease-germs  which  have  been  demonstrated, 
such  as  the  anthrax  bacillus,  the  bacterium  of 
symptomatic  anthrax,  the  micrococcus  of  fowl- 
cholera,  that  of  septicaemia  in  the  rabbit,  etc. 

H 


210  GERMICIDES  AND  ANTISEPTICS. 

Germicides  are  also  antiseptics,  as  the  bacteria  of 
putrefaction  are  killed  by  them  as  well  as  those 
mentioned.  They  may  also  arrest  putrefactive 
decomposition  in  quantities  less  than  are  required 
to  completely  destroy  putrefactive  organisms. 
But  an  antiseptic  is  not  necessarily  a  germicide  ; 
for  experiment  proves  that  certain  substances  ar- 
rest putrefaction  which  have  not  the  power  to  kill 
the  bacteria  to  which  this  is  due.  This  they  do 
by  arresting  the  vital  activity  —  multiplication  — 
of  the  germs  of  putrefaction,  or  by  so  changing 
the  nutritive  pabulum  required  for  the  develop- 
ment of  these  germs  that  they  are  unable  to 
appropriate  it  to  their  use. 

If  it  were  proven  that  the  infectious  character 
of  every  kind  of  infective  material  depended  upon 
the  presence  of  a  specific  living  germ,  as  has  been 
shown  to  be  true  in  the  case  of  certain  kinds  of 
infective  material,  germicide  and  disinfectant  would 
be  synonymous  terms.  Although  this  has  not 
been  proved,  it  is  a  significant  fact  that  all  of  the 
disinfectants  of  established  value  have  been  shown 
by  laboratory  experiments  to  be  potent  germi- 
cides. 

The  antiseptic  value  of  a  substance  is  readily 
determined  by  a  series  of  experiments  in  which  it 
is  added  in  various  proportions  to  putrescible  or- 
ganic substances,  and  observing  if,  under  favorable 
conditions  as  to  temperature  and  moisture,  putre- 
faction is  arrested  or  prevented. 

Some  observers  have  made  arrest  of  motion  in 


GERMICIDES  AND   ANTISEPTICS.    -  211 

the  motile  bacteria  a  test  of  germicide  power. 
But  it  is  evident  that  this  is  unreliable,  and  the 
only  safe  test  is  failure  to  multiply,  under  favora- 
ble conditions,  in  a  suitable  culture-fluid.  This 
test  requires  care  in  its  application,  as  contamina- 
tion of  the  culture-fluid  by  other  organisms  than 
those  which  have  been  subjected  to  the  action  of 
the  germicide  agent  would  give  a  misleading 
result. 

The  method  adopted  by  the  writer  in  a  series  of 
experiments,  the  results  of  which  are  published  in 
the  "  American  Journal  of  the  Medical  Sciences," 
April,  1883,  is  very  satisfactory  and  reliable.  This 
consists  in  the  use  of  the  little  culture-flasks,  con- 
taining a  sterilized  organic  infusion,  prepared  as 
directed  on  p.  176  of  the  present  volume. 

The  bacteria  which  serve  as  a  test  are  subjected 
to  the  action  of  the  germicide  in  a  small  glass 
tube,  previously  sterilized  by  heat;  and,  after  a 
given  time,  which  in  the  experiments  referred  to 
was  two  hours,  the  fluid  in  the  culture-flask  is  in- 
oculated with  a  minute  drop  of  fluid  from  the  tube 
containing  the  test-organisms.  The  culture-flask 
is  then  placed  in  the  oven,  at  a  temperature  of 
98°- 100°  Fahr.  At  the  end  of  twenty-four  to 
forty-eight  hours,  inspection  of  the  little  flask  will 
show  in  a  very  definite  manner  whether  the  ger- 
micide has  been  effectual  or  not :  for  the  fluid 
will  remain  unchanged  and  transparent  if  the  test- 
organisms  were  killed  by  the  germicide  agent ;  or, 
in  case  of  failure,  will  have  broken  down,  and  will 


212  GERMICIDES  AND  ANTISEPTICS. 

present  an  opalescent  or  milky  appearance,  from 
the  abundant  development  which  has  taken  place 
as  the  result  of  inoculation. 

When  a  pathogenic  organism  is  used  to  test 
the  germicide  power  of  chemical  substances,  we 
may  inoculate  living  animals  instead  of  sterilized 
culture-fluids.  In  this  case,  failure  to  produce  the 
characteristic  symptoms  of  the  disease  is,  of  course, 
to  be  taken  as  evidence  that  the  vitality  of  the 
pathogenic  germs  was  destroyed  before  inocula- 
tion. The  most  available  organisms  for  such  ex- 
periments, in  the  present  state  of  science,  are  the 
bacillus  of  anthrax,  the  micrococcus  of  fowl-chol- 
era, the  bacterium  of  symptomatic  anthrax,  and 
the  micrococcus  of  induced  septicaemia  in  the 
rabbit. 

In  a  series  of  experiments  made  by  the  writer 
in  1881,  the  last-named  organism,  as  found  in  the 
blood  of  a  rabbit  recently  dead,  served  as  the  test. 
The  results  were  on  the  whole  quite  satisfactory 
and  definite  ;  but  there  are  certain  sources  of  error 
connected  with  this  method  which  should  be  borne 
in  mind.  First.  The  test-organistn  may  be  modi- 
fied as  regards  reproductive  activity  without  being 
killed ;  and,  in  this  case,  a  modified  form  of  dis- 
ease may  result  from  the  inoculation,  of  so  mild 
a  character  as  to  escape  observation.  Second.  An 
animal  which  has  suffered  this  modified  form  of 
disease,  enjoys  protection,  more  or  less  perfect, 
from  future  attacks,  and  if  used  for  a  subsequent 
experiment  may,  by  its  immunity  from  the  effects 


GERMICIDES  AND  ANTISEPTICS.  213 

of  the  pathogenic  test-organism,  give  rise  to  the 
mistaken  assumption  that  this  had  been  destroyed 
by  the  action  of  the  germicide  agent  to  which  it 
had  been  subjected. 

Vaccine  virus  has  also  been  used  by  the  writer, 
and  by  other  experimenters,  to  test  the  compara- 
tive value  of  disinfectants.  The  method  consists 
in  dividing  a  certain  quantity  of  virus  from  the 
same  source  into  two  parts,  and  subjecting  one 
portion  to  the  action  of  the  agent  to  be  tested, 
while  the  other  is  reserved  to  prove  the  reliability 
of  the  material  used.  A  negative  result  from  vac- 
cination with  the  disinfected  virus,  and  a  positive 
result  from  that  not  disinfected,  is  evidence  of  the 
power  of  the  disinfectant  used  to  destroy  the  in- 
fective virulence  of  the  material.  The  experiment 
must  of  course  be  made  upon  unvaccinated  chil- 
dren, and  it  is  best  to  make  it  in  duplicate,  two 
punctures  being  made  upon  one  arm  with  the 
disinfected  virus,  and  two  in  the  other  with  that 
not  disinfected. 

A  complete  resume  of  the  experiments  which 
have  been  made  to  determine  the  value  of  anti- 
septics and  disinfectants  would  require  more  space 
than  can  be  given  to  this  subject  in  the  present 
volume.  Nor  can  the  results  obtained  by  different 
methods  be  brought  together  in  tabular  form ;  for 
discrepancies  exist,  due  to  various  circumstances, 
and  an  extended  discussion  would  be  required  to 
reconcile  these,  or  to  determine  which  were  en- 
titled to  the  greatest  consideration.  These  dis- 


214  GERMICIDES  AND  ANTISEPTICS. 

crepancies  arise  from  the  following  circumstances : 
(a)  The  different  bacteria  which  have  been  used 
as  test-organisms  differ  within  certain  limits  as 
regards  vital  resistance  to  the  action  of  germicide 
agents.  A  like  difference  may  occur  in  a  particu- 
lar species  (b)  as  the  result  of  the  presence  or 
absence  of  reproductive  spores ;  (c)  because  of  dif- 
ferent conditions  relating  to  the  physical  character 
of  the  material  containing  the  germs;  e.g.,  solid 
or  fluid,  coagulated  masses,  etc;  (d)  from  a  differ- 
ence in  the  reaction  of  the  media  in  which  they 
are  contained ;  (e)  from  a  difference  in  the  time  of 
exposure  to  the  action  of  the  reagent. 

The  list  which  follows  is  arranged,  for  con- 
venience, in  alphabetical  order.  The  writer  has 
given  his  own  results  the  precedence  ;  and,  as  his 
experiments  were  made  -with  special  care  by  a 
method  which  offers  the  greatest  possible  security 
against  error,  he  believes  that  they  will  be  found, 
in  the  main,  to  be  trustworthy.  The  letter  S, 
enclosed  in  brackets,  will  be  used  to  designate 
these ;  while  results  obtained  from  other  sources 
will  be  followed  by  the  name  of  the  experimenter 
who  has  reported  them. 

In  the  author's  experiments,  unless  otherwise 
stated  in  the  text,  the  time  of  exposure  to  the 
action  of  the  germicide  agent  was  two  hours.  The 
septic  micrococcus,  frequently  referred  to  below 
as  one  of  the  test-organisms  employed,  is  from 
the  blood  of  a  rabbit  recently  dead,  as  the  result 
of  inoculation  with  human  saliva ;  and,  when 


GERMICIDES  AND  ANTISEPTICS.  215 

"  septicsemic  blood"  is  spoken  of,  the  blood  of  a 
rabbit  which  has  fallen  a  victim  to  this  form  of 
septicaemia  is  meant.  (Consult  bibliography  for 
titles  of  papers  by  the  writer  relating  to  this  form 
of  induced  septicaemia  in  the  rabbit.) 

Acetic  Acid.  —  This  has  the  lowest  preventive 
power  in  Group  II.  —  the  Organic  Acids  (Dougall). 

AlcoJwl  ranks  low  as  a  germicide,  but  is  not  with- 
out value  as  an  antiseptic.  Exposure  to  ninety- 
five  per  cent  alcohol  for  forty-eight  hours  did  not 
kill  the  bacteria  in  broken-down  beef- tea  (old 
stock).  The  septic  micrococcus  was  destroyed  by 
two  hours'  exposure  to  a  twenty-four  per  cent 
solution.  The  micrococcus  of  gonorrhoeal  pus 
required  a  forty  per  cent  solution  (S). 

"Pure  or  camphorated  alcohol  is  largely  used 
by  surgeons  in  France  to  wash  their  instruments, 
but  is  evidently  capable  of  giving  only  an  illusory 
safety  against  morbid  germs.  .  .  .  When  saturated 
with  camphor,  alcohol  does  not  destroy  the  virus 
of  symptomatic  anthrax"  (Arloing,  Cornevin,  and 
Thomas).  In  the  proportion  of  1:  1.5,  it  destroys 
the  bacteria  which  cause  the  acid  fermentation  of 
milk  (Molke).  1:  1.18  destroys  the  bacteria  of 
broken-down  beef-tea,  and  1 :  20  prevents  the  de- 
velopment of  these  bacteria  in  sterilized  beef- 
infusion  (de  la  Croix).  The  micrococcus  of  pus 
multiplies  freely  in  a  culture-fluid  containing  five 
per  cent  of  alcohol,  but  fails  to  multiply  in  a  so- 
lution containing  ten  per  cent.  Exposure  for  half 
an  hour  to  alcohol  in  the  proportion  of  twelve  per 


216  GERMICIDES    AND  ANTISEPTICS. 

cent  did  not  destroy  the  virulence  of  septic  blood, 
which  was  injected  into  a  rabbit  with  a  fatal  result. 
Twice  this  amount,  however,  proved  effectual  (S). 

Aluminium  Acetate.  —  The  development  of  bac- 
teria in  pease-infusion  is  prevented  by  1 :  5,250 
(Kiihn).  The  development  of  bacteria  in  un- 
boiled beef-infusion  was  prevented  by  1:  6,310; 
and  the  bacteria  of  broken-down  beef-tea  were 
destroyed  by  1:  478,  while  1:  584  failed  (de  la 
Croix). 

Aluminium  Chloride.  —  "  Group  III.  —  Salts  of 
the  Alkaline  Earths.  Here  chloride  of  aluminium 
is  highest.  .  .  .  Were  it  not  for  the  extremely 
high  preventive  point  (1:  2,000)  of  this  salt  in  the 
hay  column,  this  group  would  occupy  a  compara- 
tively subordinate  position"  (Dougall). 

Ammonia  does  not  destroy  the  virus  of  sympto- 
matic anthrax  (Arloing,  Cornevin,  and  Thomas) ; 
or  the  spores  of  the  anthrax  bacillus  (Koch). 

Aromatic  Products  of  Decomposition.  —  Bauman  first 
showed  that  phenol  is  developed  in  albuminous 
fluids  during  the  process  of  putrefaction ;  and  Sal- 
kowski  found,  in  1875,  that  old  putrid  fluids  have 
antiseptic  properties.  Wernich  has  studied  this 
subject,  and  finds  that  the  aromatic  products  of 
decomposition, —  skatol,  phenyl,  propionic  acid,  in- 
dol,  kresol,  phenyl  acetic  acid,  and  phenol,  —  arrest 
putrefaction,  when  present  in  organic  infusions  in 
small  quantities,  in  the  order  named. 

Arscnimis  Acid.  —  One  per  cent  destroys  spores 
of  bacilli  in  ten  days  (Koch). 


GERMICIDES   AND  ANTISEPTICS.  217 

Benzoic  Acid.  —  One  part  in  2,000  retards  the 
development  of  spores  (Koch).  One  part  in  1,439 
prevents  development  of  bacteria  in  unboiled  meat- 
infusion  ;  1:  2,010  does  not.  The  bacteria  of  broken- 
down  beef-tea  are  destroyed  by  1:  77,  while  1: 
121  failed  (de  la  Croix).  In  Group  II.  — the 
Organic  Acids  —  benzoic  has  the  highest  prevent- 
ive power  (Dougall.) 

Boric  Acid  in  saturated  aqueous  solution  (four 
per  cent)  failed  to  destroy  the  three  test-organisms 
employed  in  the  writer's  experiments.  But  it  pre- 
vented the  development  of  the  M.  of  pus  in  the 
proportion  of  1 :  200 ;  of  the  M.  of  septicaemia  in 
1 :  400,  and  of  B.  termo  in  1  to  800.  This  differ- 
ence, as  regards  ability  to  multiply  in  the  presence 
of  boric  acid,  accounts  for  the  fact  that  micrococci 
have  been  observed  to  be  present  in  the  pus  of 
wounds  treated  antiseptically  with  this  substance, 
although  no  evidence  of  putrefaction  could  be  dis- 
covered. A  two  per  cent  solution  destroyed  the 
virulence  of  septicsemic  blood  ;  but,  in  view  of  the 
fact  that  twice  this  amount  did  not  kill  the  micro- 
coccus  to  which  this  virulence  is  due,  it  is  evident 
that  the  result  obtained  in  inoculation  experiments 
upon  rabbits  was  due  to  the  restraining  —  anti- 
septic—  power  of  the  reagent,  and  can  not  be 
taken  as  evidence  of  germicide  power  (S).  The 
activity  of  fresh  virus  of  symptomatic  anthrax 
was  destroyed  by  boric  acid,  one  in  five  (twenty  per 
cent)  the  time  of  exposure  being  forty-eight 
hours  (Arloing,  Cornevin,  and  Thomas).  One  part 


218  GERMICIDES  AND  ANTISEPTICS. 

in  133  prevented  the  development  of  bacteria  in 
tobacco-infusion,  while  1 :  200  failed  (Bucholtz). 
One  part  in  58  prevented  the  development  of  bac- 
teria in  a  vegetable  infusion  (peas),  while  1 :  81 
failed  ;  1 :  101  failed  to  preserve  a  solution  of  egg- 
albumen  (Kiihn).  A  five  per  cent  solution  was 
found  by  Koch  to  be  inert,  the  test  being  the 
anthrax  bacillus. 

Bromine.  —  The  spores  of  bacilli  are  killed  by  a 
two  per  cent  aqueous  solution  of  bromine.  In  the 
form  of  vapor  this  agent  is  superior,  as  regards 
rapidity  of  action,  to  chlorine  and  iodine  (Koch). 
Bromine  vapor  is  the  most  active  agent  for  the 
destruction  of  the  virus  of  symptomatic  anthrax 
(Arloing,  Cornevin,  and  Thomas).  It  destroys  the 
ferment  of  sour  milk  (Bacterium  lactis)  in  the  pro- 
portion of  1 :  348  (Molke).  The  bacteria  of  broken- 
down  beef-tea  are  destroyed  by  1 :  336  ;  and  the 
development  of  bacteria  in  unboiled  meat-infusion 
is  prevented  by  1 :  5597  (de  la  Croix). 

Camphor  does  not  destroy  the  infective  proper- 
ties of  vaccine  except  when  it  is  exposed  for  at 
least  a  week  in  an  air-chamber  saturated  with  the 
volatile  oil  (Braid wood  and  Vacher).  Alcohol  sat- 
urated with  camphor  has  no  action  upon  the  fresh 
virus  of  symptomatic  anthrax  (Arloing,  Cornevin, 
and  Thomas).  One  part  to  2,500  retards  the  de- 
velopment of  anthrax  spores  (Koch). 

Carbonic  Acid.  —  Of  five  experimental  vaccina- 
tions with  lymph  subjected  to  this  gas,  three 
succeeded  (Braidwood  and  Vacher). 


GERMICIDES  AND  ANTISEPTICS.  219 

Carbonic  Oxide. — Vaccine  lymph  may  endure  at 
least  twenty-four  hours'  exposure  to  carbonic  ox- 
ide without  losing  its  specific  properties  (Braid- 
wood  and  Vacher).  This  gas  has  no  effect  upon 
bacteria,  which  readily  develop  in  it  (Hamlet). 

Carbolic  Arid,  in  the  proportion  of  one  to  two 
hundred,  destroys  B.  termo  and  the  septic  micro- 
coccus  in  active  growth,  while  1 :  25  failed  to  de- 
stroy the  bacteria  in  broken-down  beef- tea  (old 
stock) ;  the  micrococcus  of  pus  was  destroyed  by 
1 :  225.  The  development  of  all  of  these  organ- 
isms was  prevented  by  the  presence  in  a  culture- 
fluid  of  0.2  per  cent  =  1  :  500  (S).  The  micro- 
coccus  of  swine  plague  multiplies  abundantly  in 
urine  containing  1  per  cent  of  carbolic  acid,  while 
the  micrococcus  of  fowl-cholera  is  destroyed  by 
six  hours'  exposure  to  a  1  per  cent  solution  (Sal- 
mon). A  2  per  cent  solution  destroys  the  bacte- 
rium of  symptomatic  anthrax  (dried  virus),  the 
time  of  exposure  being  forty-eight  hours  (Ar- 
loing,  Cornevin,  and  Thomas).  The  multiplica- 
tion of  bacteria  in  urine  is  not  prevented  by 
1  :  100  (Haberkorn).  In  egg-albumen  develop- 
ment of  bacteria  is  prevented  by  1  :  200  (Kiihn). 
One  part  to  502  prevents  the  development  of 
bacteria  in  unboiled  meat-infusion;  but  the  bac- 
teria in  broken-down  beef-tea  are  not  destroyed 
by  a  10  per  cent  solution  (de  la  Croix).  A  5  per 
cent  solution  required  two  days  to  arrest  the 
developing  power  of  the  spores  of  Bacillus  anthmris, 
while  a  1  per  cent  solution  destroyed  the  bacilli 


220  GERMICIDES  AND  ANTISEPTICS. 

themselves  in  two  minutes.  A  solution  of  1 :  850 
prevented  the  multiplication  of  these  bacilli  in  a 
suitable  culture-medium.  Carbolic  acid  in  solu- 
tion, in  oil  or  in  alcohol,  is  without  effect  upon 
the  spores  of  B.  anthracis,  which  germinated  after 
being  immersed  110  days  and  70  days,  respec- 
tively, in  a  5  per  cent  solution  in  oil  and  in  alco- 
hol (Koch).  The  same  author  found  that  car- 
bolic acid  vapor,  at  75°  C.,  for  two  hours,  failed 
to  destroy  anthrax  spores.  Chemical  combina- 
tions with  other  substances  were  less  efficacious 
than  the  pure  acid.  A  5  per  cent  solution  of  zinc 
sulpho-carbolate  destroyed  anthrax  spores  in  five 
days ;  a  5  per  cent  solution  of  sodium  phenate,  in 
ten  days,  merely  reduced  their  power  of  develop, 
ment,  while  sodium  sulpho-carbolate  failed  to  do 
this  within  the  same  time. 

Chloral  Hydrate  failed  to  kill  the  micrococcus  of 
pus  in  the  proportion  of  10  per  cent,  but  was 
successful  in  the  proportion  of  20  per  cent  (S). 

Chloroform.  —  A  comparatively  brief  exposure  to 
chloroform  vapor  entirely  sterilizes  vaccine  lymph 
(Braid wood  and  Vacher).  Chloroform  has  no  effect 
upon  the  fresh  virus  of  symptomatic  anthrax 
(Arloing,  Cornevin,  and  Thomas).  Chloroform  is 
inert  as  regards  the  destruction  of  the  spores  of 
the  anthrax  bacillus  (Koch).  The  development 
of  bacteria  in  unboiled  beef-infusion  is  prevented 
by  1 : 103 ;  but  1  :  1.22  failed  to  destroy  the  bac- 
teria of  broken-down  beef-tea  (de  la  Croix). 

Chlorine.— Ex-p.  No.  37,  Jan.  27,  1880.— Four 


GERMICIDES  AND  ANTISEPTICS.  221 

children  were  vaccinated  with  virus  from  ivory 
points  which  had  been  exposed  for  six  hours  to  an 
atmosphere  containing  one  half  per  cent  of  chlo- 
rine (produced  by  the  action  of  hydrochloric  acid 
on  the  peroxide  of  manganese,  and  collected  over 
warm  water) ;  also  with  four  points,  from  the  same 
lot,  not  disinfected.  Result :  Vaccination  was  un- 
successful in  every  case  with  the  disinfected  points, 
and  successful  with  those  not  disinfected  (S). 
Chlorine  destroys  the  fresh  virus  of  symptomatic 
anthrax,  but  is  powerless  against  that  which  has 
been  dried  (Arloing,  Cornevin,  and  Thomas). 
Chlorine  is  classed  with  bromine,  iodine,  and 
corrosive  sublimate,  as  one  of  the  most  relia- 
ble agents  for  destroying  the  spores  of  anthrax 
(Koch).  Development  of  bacteria  in  unboiled 
beef-infusion  is  prevented  by  the  presence  of  one 
part  in  15,606,  and  the  bacteria  of  broken-down 
beef-tea  are  destroyed  by  1  :  1,061  (de  la  Croix). 

Chromic  Acid,  in  the  proportion  of  1  :  1000.  de- 
stroys the  virulence  of  septicsemic  blood  (S).  The 
development  of  anthrax  spores  is  prevented  by 
1  :  5000 ;  but  chromic  acid  and  its  salts  are  ineffi- 
cient for  the  destruction  of  these  spores  (Koch). 
Chromic  acid  was  found  to  have  a  preventive 
power  surpassing  all  others,  its  average  being 
1  :  2,200,  while  that  of  carbolic  acid  is  only  1 :  226 
(Dougall). 

Citric  Acid,  in  the  proportion  of  12  per  cent, 
proved  fatal  to  the  micrococcus  of  pus,  while  10 
per  cent  failed  (S). 


222  GERMICIDES  AND  ANTISEPTICS. 

Creosote,  in  the  proportion  of  1  :  200,  is  fatal  to 
the  micrococcus  of  pus  (S). 

Cupric  Sulphate  destroys  the  virulence  of  septi- 
csemic  blood  in  the  proportion  of  1  :  400  (S).  The 
activity  of  dried  virus  of  symptomatic  anthrax  is 
destroyed  by  a  20  per  cent  solution  —  time  of 
exposure  forty-eight  hours  (Arloing,  Cornevin,  and 
Thomas).  The  metallic  salts,  from  their  showing 
the  highest  average  preventive  power,  form 
Group  I.  Sulphate  of  copper  here  has  not  only 
the  highest  individual  average,  but  its  three  pre- 
ventive points,  in  the  three  solutions,  are  very 
much  higher  than  those  of  any  other  substance 
in  the  group  (Dougall). 

Ether  does  not  destroy  the  spores  of  bacilli  after 
thirty  days'  exposure  (Koch).  A  brief  exposure  to 
the  vapor  of  ether  destroys  the  infective  power  of 
vaccine  lymph  (Braid wood  and  Vacher). 

Eucalyptol  retards  the  development  of  the  spores 
of  bacilli  in  the  proportion  of  1 :  2,500  (Koch).  In 
the  proportion  of  1  :  205,  the  development  of  bac- 
teria in  unboiled  meat-infusion  is  prevented.  The 
bacteria  in  broken-down  beef-tea  are  not  destroyed 
by  1 :  14  (de  la  Croix). 

Ferric  Sulphate.  —  A  saturated  solution  of  this 
salt  did  not  kill  any  of  the  test-organisms,  and  the 
use  of  this  agent  as  a  disinfectant  would  evidently 
be  a  serious  error.  It  has,  however,  a  decided 
value  as  an  antiseptic,  having  prevented  the  de- 
velopment of  all  of  the  test-organisms  in  the  pro- 
portion of  1 :  200.  Although  not  fatal  to  the 


GERMICIDES  AND  ANTISEPTICS.  223 

septic  micrococcus  in  the  proportion  of  16  per 
cent,  it  prevents  the  development  of  septicaemia 
in  the  rabbit,  after  inoculation  with  septic  blood 
to  which  it  has  been  added,  in  the  proportion 
of  1  :  400  (S).  Exposure  to  a  20  per  cent  solution 
for  forty-eight  hours  did  not  destroy  the  virus 
of  symptomatic  anthrax  (Arloing,  Cornevin,  and 
Thomas). 

Fcrri  Chloridi  Tinct.  —  A  4  per  cent  solution  was 
fatal  to  the  two  species  of  Micrococcus^  but  failed  to 
kill  B.  tcrmo.  The  micrococci  were  not  destroyed 
by  a  2  per  cent  solution  (S). 

Glycerine,  in  the  proportion  of  12.5  per  cent, 
destroyed  the  virulence  of  septicaemic  blood,  but 
failed  at  10  per  cent  (S).  Glycerine  has  no  action 
upon  the  fresh  virus  of  symptomatic  anthrax 
(Arloing,  Cornevin,  and  Thomas) ;  and  is  inert  as 
regards  the  spores  of  bacilli  (Koch). 

Heat.  —  The  thermal  death-point  of  the  micro- 
coccus  of  septicaemia  (induced  septicaemia  in  the 
rabbit)  is  140°  Fahr.  (60°  C.),  the  time  of  ex- 
posure being  ten  minutes ;  that  of  the  micrococ- 
cus of  gonorrhoeal  pus  (believed  to  be  identical 
with  M.  ureae,  Cohn),  is  the  same  (S).  The 
micrococcus  of  fowl-cholera  is  destroyed  by  expo- 
sure for  fifteen  minutes  to  a  temperature  of  132° 
Fahr.  (Salmon).  Nine  or  ten  minutes'  exposure 
to  a  temperature  of  54°  C.  is  sufficient  to  com- 
pletely kill  the  bacilli  in  anthrax  blood  (Chau- 
veau).  Cohn  has  assigned  55°  C.  as  the  highest 
point  at  which  bacteria  studied  by  him  have  lived 
and  developed.  Van  Tieghem  says  that  this  tern- 


224  GERMICIDES  AND  ANTISEPTICS. 

'perature  is  -fatal  to  most  of  these  organisms;  but 
he  has  studied  a  bacillus  which  is  able  to  multiply 
and  form  spores  in  a  culture-fluid  at  a  tempera- 
ture as  high  as  74°  C.,  but  which  ceased  to  mul- 
tiply at  77°.  Miquel  had  previously  reported  the 
existence,  in  the  water  of  the  Seine,  of  an  im- 
mobile filamentous  Bacillus,  whch  supports  a  tem- 
perature of  70°  C.,  and  which  he  has  cultivated  at 
this  temperature  in  a  neutral  meakinfusion.  This 
Bacillus  was  killed  by  a  temperature  of  71°  to  72° 
C.  The  spores  of  B.  subtilis  resist  for  several  hours 
a  temperature  of  100°  C.  (212°  Fahr).  The  time 
required  to  kill  these  spores  varies  according  to  the 
nature  of  the  liquid.  In  yeast-water,  and  in  hay- 
infusion,  they  can  resist  a  boiling  temperature  for 
five  hours ;  while  in  distilled  water  they  are  killed 
after  two  or  three  hours.  A  temperature  of 
115°  C.  kills  them  very  quickly  (Chamberland). 
Desiccated  septic  blood  does  not  lose  its  virulence 
at  the  end  of  forty  days ;  or  by  being  heated  to 
100°  for  from  three  to  twenty-four  hours,  and  the 
contained  bacteria  are  capable  of  multiplication 
after  such  exposure  (Lebeden0). 

Hydrochloric  Acid,  in  the  proportion  of  1  :  200, 
destroys  the  virulence  of  septicasmic  blood  (S). 
Hydrochloric  acid  gas  destroys  the  contagion  of 
vaccine  (Braid wood  and  Vacher).  A  2  per  cent 
solution  of  muriatic  acid  kills  the  spores  of  the 
anthrax  bacillus  in  ten  days,  while  the  develop- 
ment of  these  spores  is  prevented  by  1  :  1,700 
(Koch). 


GERMICIDES  AND  ANTISEPTICS.  22 5 

* 

Hydrogen.  —  Bacteria  may  develop  in  an  atmos- 
phere of  hydrogen  (Hamlet). 

Iodine  (in  aqueous  solution  with  potassium 
iodide)  destroys  the  septic  micrococcus  in  the 
proportion  of  1 : 1,000 ;  the  micrococcus  of  pus 
and  B.  tenno  in  1 :  500.  It  prevents  the  develop- 
ment of  these  organisms  when  present  in  a  culture- 
solution  in  the  proportion  of  1  :  4,000  (S).  The 
development  of  bacteria  in  tobacco-infusion  is 
prevented  by  1  :  5,714  (Bucholz);  in  boiled  beef- 
infusion,  1 :  2,010;  in  unboiled,  1:10,020  (de  la 
Croix).  One  part  in  1,000  destroys  the  bacteria 
which  produce  the  acid  fermentation  of  milk 
(Molke) ;  and  1  :  410  the  bacteria  of  broken-down 
beef-tea  (de  la  Croix). 

Mercuric  Bichloride.  —  All  experimenters  agree  in 
placing  this  in  the  front  rank  as  a  germicide  and 
antiseptic  agent.  One  part  in  40,000  prevents 
the  development  of  the  septic  micrococcus,  and 
but  little  less  is  required  in  the  case  of  the  micro- 
coccus  of  gonorrhoeal  pus  and  of  B.  termo.  To 
destroy  the  vitality  of  bacteria  in  broken-down 
beef-tea  (old  stock)  required  1 :  10,000,  while  the 
above-mentioned  micrococci  were  killed  by  1  :  20,- 
000  (S).  The  activity  of  the  virus  of  sympto- 
matic anthrax  (dried  virus)  is  destroyed  by  1:  5,000 
(Arloing,  Cornevin,  and  Thomas).  The  bacteria 
of  broken-down  beef-infusion  are  destroyed  by  1 : 
6,500,  and  their  development  in  beef-tea  prevented 
by  1 :  10,250  (de  la  Croix).  One  part  in  20,000 
prevents  the  development  of  bacteria  in  sterilized 

15 


226  GERMICIDES  'AND   ANTISEPTICS. 

tobacco-infusion  (Bucholz).  One  part  in  1,000 
destroys  the  spores  of  Bacillus  anthracis  in  ten 
minutes  (Koch). 

Nitric  Acid  in  the  proportion  of  1 :  400  destroys 
the  virulence  of  septicaemic  blood  —  time  of  con- 
tact, half  an  hour  (S). 

Nitrous  Acid.  —  Exp.  No.  36,  Jan.  22,  1880.- 
Three  children  were  vaccinated  with  ivory  points 
which  had  been  exposed  for  six  hours  to  an  at- 
mosphere containing  one  per  cent  of  nitrous  acid 
gas  (generated  by  pouring  nitric  acid  on  copper 
filings,  and  collected  over  mercury).  Result:  Vac- 
cination was  unsuccessful  in  each  case,  with 
disinfected  points,  and  successful  with  the  non- 
disinfected  points  from  the  same  lot  (S). 

Oil  of  Mustard,  in  the  proportion  of  1 :  33,000, 
prevents  the  development  of  the  spores  of  bacilli 
(Koch.)  The  development  of  bacteria  in  unboiled 
beef-tea  is  prevented  by  1 :  3,353 ;  and  1 :  40  de- 
stroys the  vitality  of  bacteria  in  broken-down  beef- 
tea  (de  la  Croix). 

Oil  of  Turpentine  destroys  the  spores  of  bacilli 
in  five  days,  and  retards  their  development  in  the 
proportion  of  1 :  75,000  (Koch).  Turpentine  has 
no  action  upon  the  virus  of  symptomatic  anthrax 
(Arloing,  Cornevin,  and  Thomas). 

Osmic  Acid,  in  one  per  cent  solution,  destroys 
the  spores  of  bacilli  in  one  day  (Koch). 

Oxalic  Acid,  in  saturated  solution,  destroyed  the 
virulence  of  the  fresh  virus  of  symptomatic  an- 
thrax, but  had  no  effect  upon  dried  virus  (Arloing, 
Cornevin,  and  Thomas). 


GERMICIDES   AND   ANTISEPTICS.  227 

Ozone  impairs,  and,  if  maintained  long  in  con- 
tact, destroys  the  activity  of  vaccine  lymph  (Braid- 
wood  and  Vacher).  All  germs  suspended  in  the 
air,  capable  of  developing  in  solutions  of  yeast 
from  beer,  are  killed  by  ozone  (Chappuis). 

Oxygen.  —  The  experiments  of  Pasteur  upon  the 
attenuation  of  virus  show  that  long  exposure  to 
the  oxygen  of  the  atmosphere  reduces  the  repro- 
ductive activity  of  the  micrococcus  of  fowl-cholera 
and  of  the  anthrax  bacillus,  and  that  after  a  time 
the  vitality  of  these  organisms  is  destroyed.  The 
spores  of  the  anthrax  bacillus  are,  however,  un- 
affected by  prolonged  exposure.  Out  of  twelve 
experimental  vaccinations  with  vaccine  exposed  to 
oxygen  (time  of  .exposure  one  to  seven  days),  but 
one  was  successful,  and  in  this  case  there  is  reason 
to  believe  that  the  exposure  was  imperfect  (Braid- 
wood  and  Vacher). 

Picric  Add  prevents  the  development  of  the 
spores  of  bacilli  in  the  proportion  of  1 :  5,000 
(Koch).  The  development  of  bacteria  in  beef- 
infusion  is  prevented  by  1 :  2,005,  and  the  bacteria 
of  broken-down  beef-tea  are  destroyed  by  1 :  100 
(de  la  Croix). 

Potash.  —  Caustic  potash  in  the  proportion  of 
two  per  cent  was  fatal  to  the  micrococcus  of  sep- 
ticaemia in  one  experiment,  and  failed  in  another ; 
eight  per  cent  failed  to  kill  the  micrococcus  of  pus, 
while  ten  per  cent  was  successful ;  ten  per  cent 
failed  to  destroy  the  bacteria  in  broken-down  beef- 
tea,  and  twenty  per  cent  was  successful  (S).  "  Caus- 


228  GERMICIDES  AND  ANTISEPTICS. 

tic  potash  has  the  minimum  of  preventive  power, 
—  1 :  10.  Such  a  mixture  is  highly  caustic  ;  still 
it  was  necessary  to  use  it  of  such  strength  as  at 
1  :  25  vibriones  and  bacteria  were  abundant " 
(Dougall). 

Potassium  Arsenite  (Fowler's  solution  of)  failed 
to  destroy  the  micrococcus  of  pus  in  the  proportion 
of  forty  per  cent.  According  to  Koch,  arsenite 
of  potash  prevents  the  development  of  anthrax 
spores  in  the  proportion  of  1 :  10,000. 

Potassium  Chlorate  in  the  proportion  of  four  per 
cent  does  not  destroy  the  virulence  of  septicsemic 
blood  (S).  "  Chlorate  of  potassium,  so  much  used 
as  a  gargle  in  stomatitis,  diphtheria,  etc.,  where  it 
is  held  to  act  by  destroying  certain  fungi  or  germs 
of  specific  poison,  has  not  only  no  preventive 
power,  but  actually  accelerates  decomposition " 
(Dougall). 

Potassium  Iodide  gave  no  evidence  of  germicide 
power ;  exposure  to  the  action  of  a  saturated  solu- 
tion did  not  prevent  the  development  of  the  bac- 
teria of  broken-down  beef-tea  (S). 

Potassium  Nitrate  failed  in  4  per  cent  solution  to 
destroy  the  virulence  of  septicsemic  blood  (S). 

Potassium  Permanganate.  —  A  2  per  cent  solution 
destroys  the  virulence  of  septicoemic  blood.  The 
micrococcus  of  pus  is  destroyed  by  1  :  800  (S).  A 
5  per  .cent  solution  destroys  the  fresh  virus  of 
symptomatic  anthrax,  but  has  no  effect  upon  the 
dried  virus  (Arloing,  Cornevin,  and  Thomas).  One 
per  cent  will  not  destroy  the  spores  of  anthrax. 


GERMICIDES   AND   ANTISEPTICS.  229 

but  in  the  proportion  of  1  :  3,000  their  develop- 
ment is  retarded  (Koch).  One  part  in  three  hun- 
dred prevents  the  development  of  bacteria  in 
unboiled  beef-infusion ;  and  one  part  in  thirty- 
five  kills  the  bacteria  of  broken-down  beef-tea  (de 
la  Croix). 

Pyrogallic  Acid.  —  A  solution  of  one  or  two  per 
cent  prevents,  for  some  months,  the  development 
of  odors  and  of  microscopic  organisms ;  a  solu- 
tion of  2.5  per  cent  removes  the  odor  from  fluids 
in  a  state  of  putrefaction,  and  destroys  bacteria 
(Bovet). 

Pyroligneous  Acid  destroys  the  spores  of  the  An- 
thrax bacillus  in  two  days  (Koch). 

Quinine.  —  A  10  per  cent  solution  of  sulphate  of 
quinine  has  no  action  upon  the  bacterium  of  symp- 
tomatic anthrax  (Arloing,  Cornevin,  and  Thomas). 
One  per  cent  of  quinine,  dissolved  with  muriatic  acid, 
destroys  the  spores  of  bacilli  after  ten  days'  ex- 
posure (Koch).  The  development  of  bacteria  in 
a  culture-fluid  inoculated  with  a  drop  of  turbid 
fluid  from  malarial  soil  is  prevented  by  a  solution 
of  muriate  of  quinine  of  1  :  900.  From  1 :  1,000 
to  1 :  1,500  non-putrid  development  begins.  In  a 
gelatine-culture  from  malarial  soil  no  development 
occurred  in  solutions  containing  1 :  1,500 ;  non- 
putrid  development  occurred  from  1 :  2,000  up  to 
1  :  3,000 ;  and  the  development  was  accompanied 
by  putrefaction  when  less  than  1  :  9,000  was  used 
(Ceri). 

Salicylic  Acid. — In  the  writer's  experiments,  this 


230  GERMICIDES  AND  ANTISEPTICS. 

reagent  was  dissolved  by  means  of  sodium  bibo- 
rate,  which,  by  itself,  in  saturated  solution,  has  no 
germicide  power.  A  two  per  cent  solution  was 
found  to  destroy  the  micrococcus  of  pus  and  B. 
termo  in  active  growth ;  4  per  cent  failed  to  destroy 
the  bacteria  in  broken-down  beef-tea  (old  stock). 
In  the  proportion  of  1 :  200,  this  solution  prevented 
the  development  of  the  micrococcus  mentioned ; 
in  1 :  800,  that  of  B.  termo;  and  the  septic  micro- 
coccus  in  1 :  400.  But  the  antiseptic  power  exhib- 
ited by  these  figures  does  not  differ  from  that 
obtained  by  the  use  of  the  solvent  employed  when 
used  alone.  The  virus  of  symptomatic  anthrax  is 
destroyed  by  forty-eight  hours'  exposure  to  a  solu- 
tion of  salicylic  acid  of  1  :  1,000,  and  by  saturated 
salicylic  alcohol  (Arloing,  Cornevin,  and  Thomas). 
Salicylic  acid  dissolved  in  oil  and  in  alcohol,  in  5  per 
cent  solution,  does  not  destroy  the  spores  of  the 
anthrax  bacillus  (Koch).  1  :  200  destroys  the  bac- 
teria of  sour  milk  (Molke).  1 :  343  killed  the 
bacteria  of  beef-tea,  and  1  :  1,121  prevented  the  de- 
velopment of  bacteria  in  unboiled  meat-infusion 
exposed  to  the  air  (de  la  Croix).  The  bacteria 
of  tobacco-infusion  were  destroyed  by  1  :  362, 
and  their  multiplication  prevented  by  1  :  932 
(Bucholz).  1  :  724  prevented  the  development 
of  bacteria  in  a  vegetable  infusion,  and  1 :  1,000 
in  a  solution  of  egg-albumen  (Kiihn). 

Soda.  —  Caustic  soda  destroys  the  virulence  of 
septicaemic  blood  in  the  proportion  of  1  :  400  (S). 
A  one-in-five  solution  of  soda  destroys  the  virus 


GERMICIDES  AND   ANTISEPTICS.  231 

of  symptomatic  anthrax  when  fresh,  but  has  no 
effect  upon  dried  virus  (Arloing,  Cornevin,  and 
Thomas). 

Sodium  Biborate.  —  The  results  obtained  with 
this  salt  correspond,  in  the  writer's  experiments, 
with  those  given  by  boric  acid.  The  virulence  of 
septic  blood,  as  shown  by  inoculation  of  rabbits, 
was  destroyed  by  2.5  per  cent,  while  1.25  per  cent 
failed.  That  this  is  not  due  to  germicide  power 
is  shown  by  the  fact  that  a  saturated  solution 
does  not  kill  the  septic  micrococcus,  as  proved  by 
culture-experiments.  It  also  failed  with  B.  termo 
and  the  M.  of  pus.  The  multiplication  of  all  of 
these  organisms  was,  however,  prevented  by  the 
presence  of  1  :  200  in  a  culture -fluid,  and  B.  termo 
failed  to  multiply  in  the  presence  of  1  :  400  (S). 
A  20  per  cent  solution  does  not  destroy  the  viru- 
lence of  the  virus  of  symptomatic  anthrax,  as 
proved  by  inoculation  experiments  (Arloing, 
Cornevin,  and  Thomas).  In  the  proportion  of 
1  :  107,  the  development  of  bacteria  in  unboiled 
beef-infusion  is  prevented,  while  1  :  161  failed. 
1  :  12  failed  to  kill  the  bacteria  in  broken  down 
beef-tea  (de  la  Croix). 

Sodium  Chloride,  in  5  per  cent  solution,  failed 
to  destroy  the  virulence  of  septicaemic  blood  (S). 
Common  salt  ranks  low  as  a  preventive  (Dougall). 
It  is  well  known  that  meat  may  become  putrid  in 
a  weak  solution  of  brine,  but  the  extended  use  of 
salt  as  a  preservative  agent  demonstrates  its  anti- 
septic power,  when  used  in  a  sufficiently  strong 


232  GERMICIDES   AND   ANTISEFIICS. 

solution.  It  is  doubtful,  however,  whether  infec- 
tious disease  germs  (spores)  would  be  destroyed 
by  the  most  concentrated  solution.  "  A  saturated 
solution  of  cloride  of  sodium  did  not  destroy  the 
virus  of  symptomatic  anthrax  in  forty-eight  hours' 
contact"  (Arloing,  Cornevin,  and  Thomas). 

Sodium  Hyposulphite.  —  This  salt,  in  the  writer's 
experiments,  gave  no  evidence  whatever  of  germi- 
cide power.  In  saturated  solution  it  failed  to  kill 
the  bacteria  in  broken-down  beef-tea,  and  the  M. 
of  pus  was  not  destroyed  by  exposure  for  two 
hours  to  a  thirty-two  per  cent  solution.  Nor  was 
the  development  of  the  last-named  organism  pre- 
vented by  the  presence  of  this  salt  in  a  culture- 
solution  in  the  proportion  of  eight  per  cent  (S). 
Exposure  for  forty-eight  hours  to  a  fifty  per  cent 
solution  does  not  destroy  the  virus  of  symptomatic 
anthrax  (Arloing,  Cornevin,  and  Thomas).  Chloride 
of  lime,  hard  soap,  chloral um,  and  common  salt 
are  low  preventives.  The  hyposulphite,  borate,  and 
sulphate  of  soda  are  useless  as  such  (Dougall). 

Sodium  Sulphite.  —  The  results  obtained  corre- 
spond with  those  reported  in  the  case  of  sodium 
hyposulphite  (S.) 

Sodium  Salicylate  failed  to  destroy  any  of  the  test- 
organisms  used  in  the  writer's  experiments,  in  the 
proportion  of  four  per  cent.  But  the  virulence  of 
septicsemic  blood  was  destroyed  by  1.25  per  cent ; 
it  must  therefore  have  a  restraining  influence  upon 
the  development  of  the  septic  micrococcus,  and 
doubtless  upon  other  forms  of  bacteria  also. 


GERMICIDES  AND  ANTISEPTICS.  233 

Sulphuric  Acid  destroys  B.  termo  and  the  two 
species  of  micrococcus  experimented  upon  in  the 
proportion  of  1 :  200  ;  but  a  four  per  cent  solution 
failed  to  destroy  the  bacteria  in  broken-down  beef- 
tea  (old  stock),  doubtless  because  of  the  presence 
of  reproductive  spores.  The  multiplication  of  the 
bacteria  mentioned  was  prevented  by  the  presence 
of  this  acid  in  a  culture-solution,  in  the  proportion 
of  1 :  800  (S).  One  part  in  3,353  prevented  the 
development  of  bacteria  in  unboiled  meat-infusion, 
and  1 :  72  destroyed  the  bacteria  of  broken-down 
beef- tea  (de  la  Croix).  One  part  in  161  destroyed 
bacteria  developed  in  tobacco-infusion  (Bucholz). 

Sulphurous  Acid.  —  Exp.  No.  35,  Jan.  15,  1880. 
—  Five  children  were  vaccinated  from  ivory  points 
which  had  been  exposed  for  six  hours  to  an  atmos- 
phere (dry)  containing  one  per  cent  of  sulphur 
dioxide  (collected  over  mercury),  and  with  five 
other  points,  from  the  same  lot,  not  disinfected. 
Result :  Vaccination  was  unsuccessful  in  each  case 
with  the  disinfected  points,  and  successful  with 
those  not  disinfected  (S).  In  four  experiments  in 
which  <3ry  vaccine  was  exposed  to  the  fumes  of 
sulphurous  acid,  for  ten  minutes,  its  infecting 
power  was  destroyed  (Baxter).  Sulphurous  acid 
has  no  influence  upon  the  bacteria  of  symptomatic 
anthrax  (Arloing,  Cornevin,  and  Thomas).  It  is 
powerless  against  the  spores  of  the  anthrax  bacillus 
(Koch).  In  the  proportion  of  1  :  12,649,  the  de- 
velopment of  bacteria  in  uncooked  beef-infusion  is 
prevented,  and  in  1 :  135  it  destroys  the  vitality 


234  GERMICIDES  AND  ANTISEPTICS. 

of  the  bacteria  of  broken-down  beef-tea  (de  la 
Croix). 

Sulphuretted  Hydrogen.  —  Bacteria  develop  read- 
ily in  the  presence  of  sulphuretted  hydrogen 
(Hamlet). 

Tannic  Acid,  in  the  proportion  of  one  per  cent, 
destroys  the  virulence  of  septic  blood  (S).  A  one- 
in-five  solution  of  tannic  acid  has  no  effect  upon 
the  virus  of  symptomatic  anthrax  (Arloing,  Corne- 
vin,  and  Thomas).  A  five  per  cent  solution  does 
not  kill  the  spores  of  anthrax  (Koch). 

Thymol  dissolved  in  alcohol  destroys  the  virulence 
of  septicaemic  blood  (time  of  exposure  half  an 
hour),  in  the  proportion  of  1  :  400  (S).  Thymol 
retards  the  development  of  anthrax  spores  in  the 
proportion  of  1 :  80,000  (Koch).  One  part  in  200 
kills  the  bacteria  of  tobacco-infusion  (Bucholz) ; 
one  part  in  50  the  sour-milk  ferment  (Molke) ; 
and  one  in  20  the  bacteria  of  broken-down  beef- 
tea  (de  la  Croix).  The  development  of  bacteria 
in  unboiled  beef-infusion  is  prevented  by  1 :  1,340 
(de  la  Croix),  and  in  Pasteur's  fluid  by  1 :  2,000 
(Bucholz). 

Zinc  Chloride  destroys  the  micrococcus  of  gon- 
orrhceal  pus  in  the  proportion  of  two  per  cent ; 
the  septic  micrococcus  failed  to  multiply  after  ex- 
posure to  one  part  in  200  (S).  A  five  per  cent 
solution  failed  within  a  month  to  weaken  the  de- 
veloping power  of  splenic  fever  spores  (Koch). 
Liquor  zinci  chloridi  (Squibbs)  failed  to  kill  the 
micrococcus  of  pus,  in  the  proportion  of  eight  per 
cent  (S). 


GERMICIDES  AND   ANTISEPTICS.  235 

Zinc  Sulphate,  in  the  proportion  of  twenty  per 
cent,  does  not  kill  the  micrococcus  of  pus  ;  but  in 
the  proportion  of  1.25  per  cent,  it  destroys  the 
virulence  of  septicaemic  blood.  This  is  no  doubt 
due  to  restraining  power,  and  cannot  be  taken  as 
evidence  that  the  vitality  of  the  septic  micrococcus 
was  destroyed  (S). 


PART  FIFTH. 


BACTERIA  IN  INFECTIOUS  DISEASES. 

No  more  important  question  has  ever  engaged 
the  attention  of  physicians,  of  sanitarians,  or  of 
biologists,  than  that  which  relates  to  the  role  of 
the  bacteria  in  infectious  diseases.  The  practical 
results  of  etiological  studies,  so  far  as  the  preven- 
tion and  cure  of  disease  are  concerned,  are  likely 
to  be  much  greater  than  those  which  have  been 
gained  by  the  study  of  pathological  anatomy;  and,  if 
the  time  ever  comes,  as  now  seems  not  improbable, 
when  we  can  say  with  confidence,  infectious  diseases 
are  parasitic  diseases,  medicine  will  have  established 
itself  upon  a  scientific  foundation.  But  this  gener- 
alization, which  some  physicians  think  is  justified, 
even  now,  by  the  experimental  evidence  which  has 
been  so  rapidly  accumulating  during  the  past  de- 
cade, would,  in  the  opinion  of  the  writer,  be  prem- 
ature in  the  present  state  of  science.  And,  for  the 
present,  it  seems  wiser  to  encourage  additional 
researches  rather  than  to  attempt  to  generalize 
from  the  data  at  hand.  For  much  of  the  evidence 
offered  in  favor  of  this  view  is  open  to  question ; 


BACTERIA  IX  INFECTIOUS  DISEASES.  237 

and  even  where  we  do  not  doubt  the  scientific 
accuracy  of  an  observer,  we  may  differ  from  him 
as  to  the  interpretation  of  the  facts  which  he  has 
recorded.  Those  who  have  had  the  most  experi- 
ence in  this  difficult  field  of  investigation,  are 
commonly  the  most  critical  and  exacting  with 
reference  to  the  alleged  discoveries  of  others. 
And  it  is  now  generally  admitted  that  the  only 
satisfactory  proof  that  a  certain  micro-organism 
bears  a  causal  relation  to  a  disease  with  which  it 
is  associated  is  that  which  is  obtained  by  a  series 
of  culture  experiments,  in  which  the  organism  is 
completely  isolated  from  the  non-living  constitu- 
ents of  the  infective  material  containing  it,  and 
in  the  production  of  the  disease  in  question  by 
inoculation  experiments  with  such  a  "  pure-cul- 
ture." The  unimpeachable  nature  of  this  proof, 
when  the  experiment  is  properly  made  and  fre- 
quently repeated  with  the  same  result,  is  made 
apparent  in  the  following  quotation  from  a  paper 
by  the  writer  relating  to  "  a  fatal  form  of  septi- 
caemia in  the  rabbit." l 

"  In  my  previous  paper  I  related  a  series  of  experi- 
ments commenced  July  6th,  to  which  I  must  refer  the 
reader  as  properly  introducing  the  following  :  - 

"  The  culture-fluid  (No.  6)  used  in  Experiment  No.  3 
(July  26th)  was  laid  aside  in  an  hermetically-sealed 
culture-flask  until  September  12th,  when  a  minute  drop 
was  used  to  inoculate  sterilized  bouillon  in  culture-tube 
No.  7,  This,  placed  in  a  culture-oven  at  100°  Fahr.  for 
twenty-four  hours,  became  clouded,  and  upon  micro- 
i  Med.  Times,  Phila.,  Nov.  4th,  1882,  p.  81. 


238  BACTERIA  IN  INFECTIOUS  DISEASES. 

scopical  examination  proved  to  be  pervaded  with  the 
identical  micrococcus  heretofore  described  and  photo- 
graphed (See  Fig.  2,  Plate  IX.).  A  drop  of  culture 
No.  7  was  in  like  manner  used  to  inoculate  culture  No. 
8,  and  the  next  day,  this  being  also  pervaded  by  the 
micrococcus,  was  used  in  the  following  experiment :  — 

"  Exp.  No.  4.  —  September  14th.  —  Injected  ten 
minims  of  culture  No.  8  into  a  full-grown  rabbit.  Result : 
This  animal  died  at  9  A.  M.  September  15th,  and  a  micro- 
scopical examination  made  at  once  demonstrated  the 
presence  of  the  micrococcus  in  great  numbers  in  the 
blood  and  in  effused  serum  in  the  sub-cutaneous  connec- 
tive tissue. 

u  Remarks.  —  This  experiment  shows  that  the  micro- 
coccus  retained  its  vitality  and  its  full  virulence  at  the 
end  of  six  weeks,  and,  very  conclusively,  that  the  viru- 
lence of  the  culture-fluid  is  due  to  the  presence  of  the 
micrococcus,  and  not  to  a  hypothetical  chemical  virus 
found  in  the  first  instance  in  human  saliva  and  subse- 
quently in  the  blood  of  a  rabbit  inoculated  with  this 
fluid.  For  the  benefit  of  those  who  have  not  calculated 
the  degree  of  dilution  which  such  a  hypothetical  chemi- 
cal virus  would  undergo  in  such  a  series  of  culture  ex- 
periments, I  submit  the  following  simple  calculation  :  - 

"My  culture-tubes  contain  about  a  fluidrachm  of 
sterilized  bouillon.  The  amount  of  blood  introduced 
into  culture  No.  1,  as  seed,  was  considerably  less  than  a 
minim ;  but  for  convenience  I  will  suppose  that  one 
minim  is  used  each  time  to  start  a  new  culture,  —  that  is, 
the  original  material  is  diluted  60  times  in  the  first  cul- 
ture, 3,600  times  in  the  second,  216,000  times  in  the 
third,  and  in  the  eighth  culture  it  will  be  present  in  the 
proportion  of  one  part  in  1,679,611,600,000,000.  Yet  a 
few  minims  of  this  eighth  culture  possesses  all  the  viru- 
lence of  the  first. 


BACTERIA  IN   INFECTIOUS  DISEASES.  239 

"  Look  at  it  from  another  point  of  view.  The  few 
minims  of  culture-fluid  introduced  beneath  the  skin  of 
a  rabbit  contain  a  micrococcus  presenting  definite  mor- 
phological characters.  The  blood  of  the  animal  which 
falls  a  victim  to  experimental  inoculation  with  this  fluid 
is  filled  within  forty-eight  hours  with  the  same  micro- 
organism in  numbers  far  exceeding  the  normal  histo- 
logical  elements,  —  red  and  white  corpuscles  ;  yet  some 
very  conservative  physicians  still  claim  that  the  invading 
parasite  is  without  import,  a  mere  epi-phenomenon, 
while  the  infinitesimal  portion  of  a  hypothetical  chemi- 
cal virus  is  credited  with  this  malignant  potency." 

When,  in  addition  to  this,  we  remember  that 
potent  chemical  poisons,  especially  when  injected 
subcutaneously,  act  promptly,  and  that  their  poi- 
sonous effect  bears  a  relation  to  the  dose  in  which 
tbey  are  administered,  whereas  a  rabbit  subjected 
to  an  experimental  inoculation  with  septic  blood, 
or  with  a  culture-fluid  remotely  inoculated  with 
this  material,  shows  no  signs  of  ill-health  for  many 
hours,  —  eighteen  hours  or  more,  —  and  that  it  is 
only  when  sufficient  time  has  elapsed  to  permit  of 
the  abundant  development  of  the  micrococcus  that 
serious  symptoms  are  developed,  we  shall  see  that 
but  one  conclusion  can  be  drawn  as  regards  the 
role  of  the  micrococcus. 

It  is  by  experimental  evidence  of  tbis  nature 
that  Koch,  Pasteur,  and  many  others  have  demon- 
strated beyond  question  that  the  disease  known  as 
anthrax  is  produced  by  a  parasitic  micro-organism, 
—  the  Bacillus  anthrads  ;  that  the  last-named  in- 
vestigator has  established  the  etiological  role  of  the 


240  BACTERIA  IN   INFECTIOUS  DISEASES. 

micrococcus  of  fowl-cholera ;  and  that  Koch  has 
proved  that  a  form  of  induced  septicaemia  in  mice, 
which  he  has  especially  studied,  is  due  to  a  minute 
bacillus. 

It  has  been  suggested  that  the  parasitic  micro- 
organism in  these  diseases  is,  perhaps,  only  a  second- 
ary cause,  being  merely  a  carrier  of  the  non-living 
ferment,  which  is  the  special  poison  of  the  disease. 
This  hypothesis,  also,  is  excluded  by  inoculation 
experiments  with  a  pure-culture,  sufficiently  re- 
moved from  the  natural  infective  material.  For 
the  organisms  introduced  into  culture  No.  1,  as 
seed,  disappear  as  quickly  from  successive  cultures 
as  does  the  non-living  material  with  which  they  are 
associated,  and  we  may  very  soon  leave  them  out 
of  the  account,  although  each  successive  culture- 
fluid  is  invaded  throughout  by  their  numerous 
progeny. 

Having  determined  for  a  certain  infectious  dis- 
ease that  its  transmissibility  depends  upon  the 
presence  in  the  infective  material  of  a  living  micro- 
organism, the  question  naturally  arises  as  to  the 
modus  operandi  of  this  parasite.  Does  it  produce 
death  by  appropriating  something  from  the  vital 
fluid,  or  from  the  tissues  invaded  by  it,  —  e.  g.,  oxy- 
gen, which  is  essential  for  the  maintenance  of  vital 
processes  in  the  living  animal  ?  Or  does  it,  at  the 
same  time  that  it  appropriates  material  for  its  own 
nutrition,  evolve  some  poisonous  chemical  product 
which  is  the  immediate  cause  of  the  morbid  pheno- 
mena in  the  infected  animal  ?  Or  does  ii,  produce 


BACTERIA  IN   INFECTIOUS  DISEASES.  241 

death  by  the  mechanical  effects  which  result  from 
its  presence  in  such  vast  numbers,  i.  e.,  by  blocking 
up  the  capillaries  and  the  formation  of  emboli  ? 

There  can  be  little  doubt  that,  in  these  acute 
infectious  diseases,  the  parasite  injures  its  host  in 
all  three  of  the  ways  indicated,  and  that  a  fatal 
result  is  to  be  ascribed  to  the  three  causes  men- 
tioned conjointly. 

A  most  difficult  and  important  question  in  con- 
nection with  these  diseases  is  that  which  relates  to 
the  rationale  of  the  immunity  produced  by  protec- 
tive inoculations  practised  by  one  of  the  methods 
described  in  PART  FOURTH  of  the  present  volume. 
In  these  protective  vaccinations,  the  virus  used  is 
either  greatly  diluted  or  is  modified  as  regards  the 
reproductive  activity  of  the  parasite  by  exposure 
to  oxygen,  by  heat,  or  by  certain  chemical  re- 
agents. A  susceptible  animal,  when  inoculated 
with  virus  "  attenuated  "  by  one  of  these  methods, 
does  not  succumb  to  the  attacks  of  the  parasite, 
but,  after  experiencing  a  mild  form  of  the  disease, 
recovers,  and  is  subsequently  protected  from  the 
effects  of  full  doses  of  unmodified  virus. 

This  recovery  after  inoculation  with  attenuated 
virus  is  more  easy  to  understand  than  is  the  subse- 
quent protection.  There  is  evidently  some  pro- 
vision of  nature  by  which  invading  organisms  may 
be  disposed  of  when  they  do  not  multiply  too 
quickly,  but  which  fails  when  they  have  very 
great  reproductive  activity,  and  when  the  con- 
ditions within  the  living  animal  are  extremely 

16 


242  BACTERIA  IN   INFECTIOUS    DISEASES. 

favorable  to  their  development.  These  conditions 
doubtless  relate  mainly  to  the  composition  and 
temperature  of  the  culture-medium  —  i.e.,  of  the 
blood  of  the  animal  —  and  consequently  vary  in 
different  species  of  animals.  But  that  the  compo- 
sition of  the  blood  should  be  changed  materially 
and  permanently  in  the  same  animal,  as  a  result 
of  the  mild  form  of  disease  which  follows  pro- 
tective inoculation,  it  is  difficult  to  believe.  Yet 
this  is  the  explanation  given  by  Pasteur  of  the 
immunity  afforded  by  such  inoculations.  This 
change  is  supposed  to  consist  in  the  removal  of 
some  material  essential  for  the  nutrition  of  the 
microbe,  which  is  exhausted  during  the  attack, 
and  never  reproduced.  This  view  is  sustained 
in  the  following  language :  — 

"  It  is  the  life  of  a  parasite  in  the  interior  of  the  body 
which  produces  the  malady  commonly  called  4  cholera 
des  poulesj  and  which  causes  death.  From  the  moment 
when  this  culture  (i.  e.,  the  multiplication  of  the  para- 
site) is  no  longer  possible  in  the  fowl,  the  sickness  can- 
not appear.  The  fowls  are  then  in  the  constitutional 
state  of  fowls  not  subject  to  be  attacked  by  the  disease. 
These  last  are  as  if  vaccinated  from  birth  for  this  mal- 
ady, because  the  foetal  evolution  has  not  introduced  into 
their  bodies  the  material  necessary  to  support  the  life  of 
the  microbe ;  or  these  nutritive  materials  have  disap- 
peared at  an  early  age. 

"  Certainly  one  should  not  be  surprised  that  there 
may  be  constitutions  sometimes  susceptible  and  some- 
times rebellious  to  inoculation  —  that  is  to  say,  to  the 
cultivation  of  a  certain  virus,  when,  as  I  have  an- 


BACTERIA  IN   INFECTIOUS  DISEASES.  243 

nounced  in  my  first  note,  one  sees  a  preparation  of  beer 
yeast  made  exactly  like  one  from  the  muscles  of  fowls 
(bouillon)  to  show  itself  absolutely  uusuited  for  the 
cultivation  of  the  parasite  of  fowl  cholera,  while  it  is 
admirably  adapted  to  the  cultivation  of  a  multitude  of 
microscopic  species,  notably  to  the  bacteride  charbon- 
neuse  (Bacillus  anthracis) . 

"  The  explanation  to  which  these  facts  conduct  us,  as 
well  of  the  constitutional  resistance  of  some  individuals, 
as  of  the  immunit}7  produced  by  protective  inoculations, 
is  only  natural  when  w,e  consider  that  every  culture,  in 
general,  modifies  the  medium  in  which  it  is  effected ; 
a  modification  of  the  soil  when  it  relates  to  ordinary 
plants;  a  modification  of  plants  and  animals  when  it 
relates  to  their  parasites ;  a  modification  of  our  culture 
liquids  when  it  relates  to  mucedines,  vibrioniem,  or 
ferments. 

44  These  modifications  are  manifested  and  character- 
ized by  the  circumstance  that  new  cultivations  of  the 
same  species  in  these  media  become  promptly  difficult 
or  impossible.  If  we  sow  chicken-bouillon  with  the  mi- 
crobe of  fowl-cholera,  and,  after  three  or  four  days, 
filter  the  liquid  in  order  to  remove  all  trace  of  the 
microbe,  and  subsequently  sow  anew  in  the  filtered 
liquid  this  parasite,  it  will  be  found  quite  powerless  to 
resume  the  most  feeble  development.  The  liquid,  which 
is  perfectly  limpid  after  being  filtered,  retains  its  limpid- 
ity indefinitely. 

"  How  can  we  fail  to  believe  that  by  cultivation  in  the 
fowl  of  the  attenuated  virus,  we  place  its  body  in 
the  state  of  this  filtered  liquid,  which  can  no  longer 
cultivate  the  microbe  ?  The  comparison  can  be  pushed 
still  further  ;  for,  if  we  filter  the  bouillon  containing  the 
microbe  in  full  development,  not  on  the  fourth  day  of 
culture,  but  on  the  second,  the  filtered  liquid  will  still 


244  BACTERIA  IN   INFECTIOUS  DISEASES. 

be  able  to  support  the  development  of  the  microbe, 
although  with  less  energy  than  at  the  outset.  \Ve 
comprehend,  then,  that  after  a  cultivation  of  the  modi- 
fied (attenue)  microbe  in  the  body  of  the  fowl,  we  may 
not  have  removed  from  all  parts  of  its  body  the  aliment 
of  the  microbe.  That  which  remains  will  permit,  then, 
a  new  culture,  but  in  a  more  restricted  measure. 

**  This  is  the  effect  of  a  first  inoculation  ;  subsequent 
inoculations  will  remove  progressively  all  the  material 
necessary  for  the  development  of  the  parasite. 

"  Is  this  the  only  possible  explanation  of  the  phenom- 
enon ?  No ;  we  may  admit  the  possibility  that  the 
development  of  the  microbe,  in  place  of  removing  or 
destroying  certain  matters  in  the  bodies  of  the  fowls, 
adds,  on  the  contrary,  something  which  is  an  obstacle  to 
the  future  development  of  this  microbe.  The  history 
of  the  life  of  inferior  beings  authorizes  such  a  supposi- 
tion. The  excretions  resulting  from  vital  processes 
may  arrest  vital  processes  of  the  same  nature.  In  cer- 
tain fermentations  we  see  antiseptic  products  make 
their  appearance  during,  and  as  a  result  of,  the  fermen- 
tation, which  put  an  end  to  the  active  life  of  the  fer- 
ments, and  arrest  the  fermentations  long  before  they 
are  completed.  In  the  cultivation  of  our  microbe,  pro- 
ducts may  have  been  formed  the  presence  of  which, 
possibly,  may  explain  the  protection  following  inocula- 
tion. 

"  Our  artificial  cultures  permit  us  to  test  the  truth  of 
this  hypothesis.  Let  us  prepare  an  artificial  culture 
of  the  microbe,  and  after  having  evaporated  it,  in  vacuo, 
without  heat,  let  us  bring  it  back  to  its  original  volume 
by  means  of  fresh  chicken  bouillon.  If  the  extract  con- 
tains a  poison  for  the  life  of  the  microbe,  and  if  this  is 
the  cause  of  its  failure  to  multiply  in  the  filtered 
liquid,  the  new  liquid  should  remain  sterile.  Now  this 


BACTERIA  IN  INFECTIOUS  DISEASES.  245 

is  not  the  case.  We  cannot,  then,  believe  that  during 
the  life  of  the  parasite  certain  substances  are  produced 
which  are  capable  of  arresting  its  ulterior  develop- 
ment."  —  (Comptes  rendus  Acad.  des  Sc.,  XC.  pp.  952- 
958.) 

It  is  a  little  surprising  that  after  disproving,  by 
the  experimental  method,  the  hypothesis  last  men- 
tioned, which  had  been  proposed  by  a  member  of 
the  French  Academy  in  explanation  of  the  phe- 
nomenon in  question,  Pasteur  did  not,  in  accord- 
ance with  his  usual  custom,  attempt  to  establish 
his  own  hypothesis  upon  a  firm  foundation  by  an 
experiment  which  at  once  suggests  itself.  If  a 
fowl  which  is  protected  against  cholera,  or  an 
animal  which  is  protected  against  anthrax,  owes 
this  protection  to  the  fact  that  a  certain  material 
which  is  required  for  the  development  of  the 
microbe  of  fowl-cholera,  or  for  the  anthrax  bacil- 
lus, has  been  exhausted  in  the  course  of  the  modi- 
fied form  of  the  disease  to  which  immunity  is  due, 
then  the  flesh  of  such  an  animal,  made  into  bouillon, 
should  not  constitute  a  proper  culture-medium  for 
the  organisms  in  question.  The  writer  ventures 
to  predict  that  the  result  of  such  an  experiment 
would  not  be  favorable  to  Pasteur's  hypothesis, 
and  that  it  will  be  found  that  the  micrococcus  of 
fowl-cholera  can  be  cultivated  in  bouillon  made  from 
the  flesh  of  a  protected  animal,  and  that  the  bacil- 
lus of  anthrax  may  multiply  freely  in  the  blood,  or 
in  an  infusion  of  the  flesh,  of  an  animal  which, 
before  it  was  killed  for  the  experiment,  possessed 


246  BACTERIA  IN  INFECTIOUS    DISEASES. 

immunity  against  the  disease  anthrax.  The  writer 
long  since  proposed  to  himself  to  make  the  experi- 
ment, but  has  not  yet  been  able  to  do  so.  The 
matter  is  mentioned  here  in  the  hope  that  some 
one  more  favorably  situated  for  pursuing  experi- 
mental work  will  consider  it  of  sufficient  impor- 
tance to  induce  him  to  test  it  in  the  manner 
indicated.  In  the  meantime  I  take  the  liberty  of 
quoting,  from  a  paper  published  in  1881,  certain 
extracts  in  which  my  reasons  are  given  for  doubt- 
ing the  correctness  of  the  hypothesis  of  Pasteur, 
and  in  which  another  explanation  is  offered :  — 

"  Let  us  see  where  this  hypothesis  leads  us.  In  the 
first  place,  we  must  have  a  material  of  small-pox,  and  a 
material  of  measles,  and  a  material  of  scarlet  fever,  etc., 
etc.  Then  we  must  admit  that  each  of  these  different 
materials  has  been  formed  in  the  system  and  stored  up 
for  these  emergencies,  —  attacks  of  the  diseases  in  ques- 
tion, —  for  we  can  scarcely  conceive  that  they  were  all 
packed  away  in  the  germ-cell  of  the  mother  and  the 
sperm-cell  of  the  father  of  each  susceptible  individual. 
If,  then,  these  peculiar  materials  have  been  formed  and 
stored  up  during  the  development  of  the  individual, 
how  are  we  to  account  for  the  fact  that  no  new  produc- 
tion takes  place  after  an  attack  of  any  one  of  the  dis- 
eases in  question  ? 

"  Again,  how  shall  we  account  for  the  fact  that  the 
amount  of  material  which  would  nourish  the  small-pox 
germ,  to  the  extent  of  producing  a  case  of  confluent 
small-pox  may  be  exhausted  by  the  action  of  the  atten- 
uated virus  (germ)  introduced  by  vaccination?  Pas- 
teur's comparison  of  a  fowl  protected  by  inoculation 
with  the  microbe  of  fowl-cholera,  with  a  culture-fluid  in 


BACTERIA  IN  INFECTIOUS   DISEASES.  247 

which  the  growth  of  a  particular  organism  has  exhausted 
the  pabulum  necessary  for  the  development  of  additional 
organisms  of  the  same  kind,  does  not  seem  to  me  to  be  a 
just  one,  as  in  the  latter  case  we  have  a  limited  supply 
of  nutriment,  while  in  the  former  we  have  new  supplies 
constantly  provided  of  the  material — food — from  which 
the  whole  body,  including  the  hypothetical  subsfance 
essential  to  the  development  of  the  disease-germ,  was 
built  up  prior  to  the  attack.  Besides  this,  we  have  a 
constant  provision  for  the  elimination  of  effete  and 
useless  products. 

44  This  hypothesis,  then,  requires  the  formation  in  the 
human  body,  and  the  retention  up  to  a  certain  time,  of 
a  variety  of  materials,  which,  so  far  as  we  can  see,  serve 
no  purpose  except  to  nourish  the  germs  of  various  spe- 
cific diseases,  and  which,  having  served  this  purpose,  are 
not  again  formed  in  the  same  system,  subjected  to  simi- 
lar external  conditions,  and  supplied  with  the  same  kind 
of  nutriment. 

44  The  difficulties  into  which  this  hypothesis  leads 
certainly  justify  us  in  looking  further  for  an  explanation 
of  the  phenomenon  in  question.  This  explanation  is,  I 
believe,  to  be  found  in  the  peculiar  properties  of  the 
protoplasm,  which  is  the  essential  frame-work  of  every 
living  organism.  The  properties  referred  to  are :  the 
tolerance  which  living  protoplasm  may  acquire  to  cer- 
tain agents  which,  in  the  first  instance,  have  an  inju- 
rious or  even  fatal  influence  upon  its  vital  activity,  and 
the  property  which  it  possesses  of  transmitting  its  pecu- 
liar qualities,  inherent  or  acquired,  through  numerous 
generations,  to  its  offshoots  or  progeny. 

44  Protoplasm  is  the  essential  living  portion  of  the  cel- 
lular elements  of  animal  and  vegetable  tissues;  but  as 
our  microscopical  analysis  of  the  tissues  has  not  gone 
beyond  the  cells  of  which  they  are  composed,  and  is  not 


248  BACTERIA  IN  INFECTIOUS  DISEASES. 

likely  to  reveal  to  us  the  complicated  molecular  struc- 
ture of  the  protoplasm  upon  which,  possibly,  the  proper- 
ties under  consideration  depend,  it  will  be  best,  for  the 
present,  to  limit  ourselves  to  a  consideration  of  the  living 
cells  of  the  body.  These  cells  are  the  direct  descend- 
ants of  pre-existing  cells,  and  may  all  be  traced  back  to 
the  s*perm-cell  and  germ-cell  of  the  parents.  Now,  the 
view  which  I  am  endeavoring  to  elucidate  is,  that  dur- 
ing a  non-fatal  attack  of  one  of  the  specific  diseases,  the 
cellular  elements  implicated,  which  do  not  succumb  to 
the  destructive  influence  of  the  poison,  acquire  a  tol- 
erance to  this  poison  which  is  transmissible  to  their 
progeny,  and  which  is  the  reason  of  the  exemption 
which  the  individual  enjoys  from  future  attacks  of  the 
same  disease. 

"  The  known  facts  in  regard  to  the  hereditary  trans- 
mission, by  cells,  of  acquired  properties,  make  it  easy  to 
believe  in  the  transmission  of  such  a  tolerance  as  we 
imagine  to  be  acquired  during  the  attack  ;  and  if  it  is 
shown  by  analogy  that  there  is  nothing  improbable  in 
the  hypothesis  that  such  a  tolerance  is  acquired,  we  shall 
have  a  rational  explanation,  not  of  heredity  and  the 
mysterious  properties  of  protoplasm,  but  of  the  partic- 
ular result  under  consideration.  The  transmission  of 
acquired  properties  is  shown  in  the  budding  and  graft- 
ing of  choice  fruits  and  flowers,  produced  by  cultiva- 
tion, upon  the  wild  stock  from  which  they  originated. 
The  acquired  properties  are  transmitted  indefinitely; 
and  the  same  sap  which  on  one  twig  nourishes  a  sour 
crab-apple,  on  another  one  of  the  same  branch  is  elab- 
orated into  a  delicious  pippin.  .  . 

"  The  tolerance  to  narcotics  —  opium  and  tobacco, 
and  to  corrosive  poisons  —  arsenic,  which  results  from  a 
gradual  increase  of  dose,  may  be  cited  as  an  example  of 
acquired  tnli-rance  by  living  protoplasm  to  poisons, 


BACTERIA   IN   INFECTIOUS  DISEASES.  249 

which  at  the  outset  would   have   been  fatal  in  much 
smaller  doses. 

"  The  immunity  which  an  individual  enjoys  from  any 
particular  disease  must  be  looked  upon  as  a  power  of 
resistance  possessed  by  the  cellular  elements  of  those 
tissues  of  his  body  which  would  yield  to  the  influence 
of  the  poison  in  the  case  of  an  unprotected  person.  .  .  . 
The  resistance  of  living  matter  to  certain  destructive 
influences  is  a  property  depending  upon  vitality.  Thus, 
living  protoplasm  resists  the  action  of  the  bacteria  of 
putrefaction,  while  dead  protoplasm  quickly  undergoes 
putrefactive  changes."  —  Am.  J.  of  the  Med.  Sciences, 
April,  1881,  p.  375. 

The  hypothesis  of  Pasteur  would  account  for 
the  fact  that  one  individual  suffers  a  severe  attack 
and  another  a  mild  attack  of  an  infectious  disease, 
after  being  subjected  to  the  influence  of  the  poison 
under  identical  circumstances,  by  the  supposition 
that  the  pabulum  required  for  the  development  of 
this  particular  poison  is  more  abundant  in  the  body 
of  one  individual  than  in  the  other.  The  expla- 
nation which  seems  to  us  more  satisfactory,  is  that 
tbe  vital  resistance  offered  by  the  cellular  elements 
in  tbe  bodies  of  these  two  individuals  was  not  the 
same  for  this  poison.  It  is  well  known  that  in 
conditions  of  lowered  vitality,  resulting  from  star- 
vation, profuse  discharges,  or  any  other  cause,  the 
power  to  resist  disease-poisons  is  greatly  dimin- 
ished, and,  consequently,  that  the  susceptibility  of 
the  same  individual  differs  at  different  times. 

From  our  point  of  view,  the  blood,  as  it  is  found 
within  the  vessels  of  a  living  animal,  is  not  simply 


250  BACTERIA  IN  INFECTIOUS   DISEASES. 

a  culture-fluid  maintained  at  a  fixed  temperature  ; 
but,  under  these  circumstances,  is  a  tissue,  the 
histological  elements  of  which  present  a  certain 
vital  resistance  to  pathogenic  organisms  which  may 
be  introduced  into  the  circulation. 

If  we  add  a  small  quantity  of  a  culture-fluid 
containing  the  bacteria  of  putrefaction  to  the  blood 
of  an  animal,  withdrawn  from  the  circulation  into 
a  proper  receptacle,  and  maintained  in  a  culture- 
oven  at  blood-heat,  we  will  find  that  these  bacteria 
multiply  abundantly,  and  evidence  of  putrefactive 
decomposition  will  soon  be  perceived.  But,  if  we 
inject  a  like  quantity  of  the  culture-fluid  with  its 
contained  bacteria  into  the  circulation  of  a  living 
animal,  not  only  does  no  increase  and  no  putrefac- 
tive change  occur,  but  the  bacteria  introduced 
quickly  disappear,  and  at  the  end  of  an  hour  or 
two  the  most  careful  microscopical  examination 
will  not  reveal  the  presence  of  a  single  bacterium. 
This  difference  we  ascribe  to  the  vital  properties 
of  the  fluid  as  contained  in  the  vessels  of  a  living 
animal ;  and  it  seems  probable  that  the  little 
masses  of  protoplasm  known  as  white  blood  cor- 
puscles are  the  essential  histological  elements  of 
the  fluid,  so  far  as  any  manifestation  of  vitality  is 
concerned. 

The  writer  has  elsewhere  suggested  that  the 
disappearance  of  the  bacteria  from  the  circulation, 
in  the  experiment  above  referred  to,  may  be 
effected  by  the  white  corpuscles,  which,  it  is  well 
known,  pick  up,  after  the  manner  of  amoebae,  any 


BACTERIA   IN   INFECTIOUS   DISEASES. 

particles,  organic  or  inorganic,  which  come  in  their 
way.  And  it  requires  no  great  stretch  of  credulity 
to  believe  that  they  may,  like  an  amoeba,  digest 
and  assimilate  the  protoplasm  of  the  captured  bac- 
terium, thus  putting  an  end  to  the  possibility  of  its 
doing  any  harm. 

In  the  case  of  a  pathogenic  organism  we  may 
imagine  that,  when  captured  in  this  way,  it  may 
share  a  like  fate  if  the  captor  is  not  paralyzed  by 
some  potent  poison  evolved  by  it,  or  overwhelmed 
by  its  superior  vigor  and  rapid  multiplication.  In 
the  latter  event,  the  active  career  of  our  conser- 
vative white  corpuscle  would  be  quickly  termin- 
ated, and  its  protoplasm  would  serve  as  food  for 
the  enemy.  It  is  evident  that  in  a  contest  of  this 
kind  the  balance  of  power  would  depend  upon  cir- 
cumstances relating  to  the  inherited  vital  charac- 
teristics of  the  invading  parasite  and  of  the  in- 
vaded leucocyte. 

That  different  pathogenic  organisms  of  the  same 
species  may  differ  as  to  their  power  to  overcome 
the  vital  resistance  of  living  animals  is  amply 
proved  by  experiment.  We  have  examples  of  this 
in  the  attenuated  virus  of  anthrax  and  of  fowl- 
cholera.  These  physiological  varieties,  as  Pasteur 
calls  them,  may  be  produced  at  will  by  one  of  the 
methods  heretofore  referred  to.  They  differ  from 
the  unmodified  virus  in  vital  activity,  and  this  is 
especially  manifested  in  their  diminished  reproduc- 
tive power. 

In  the  great  laboratory  of  nature,  like  causes 


252  BACTERIA  IN  INFECTIOUS  DISEASES. 

must  produce  similar  results;  and  there  can  be 
little  doubt  that  physiological  varieties,  or  breeds, 
of  the  different  species  of  bacteria  are  constantly 
being  produced  and  destroyed  by  the  operation  of 
natural  causes.  Under  the  influence  of  a  favorable 
temperature  and  of  abundant  pabulum,  these  mi- 
nute plants  multiply  abundantly ;  and,  in  accord- 
ance with  the  laws  of  natural  selection,  there  must 
be  a  constant  tendency  among  them  to  develop 
those  characters  which  are  most  favorable  to  their 
preservation,  —  e.  g.,  a  capacity  for  rapid  multi- 
plication, and  to  adapt  themselves  to  their  envi- 
ronment. 

If  we  suppose  that  under  certain  circumstances 
the  conditions  relating  to  environment  approach 
those  which  would  be  found  within  the  body  of  a 
living  animal,  we  can  easily  understand  how  a 
micro-organism,  which  has  adapted  itself  to  these 
conditions,  may  become  a  pathogenic  organism, 
when  by  any  chance  it  is  introduced  into  the  cir- 
culation of  such  an  animal.  The  culture-fluid  — 
blood  —  and  temperature  being  favorable,  it  is  only 
a  question  of  superiority  by  vital  resistance  on  the 
one  hand,  or  by  reproductive  activity  on  the 
other. 

That  harmless  species  of  bacteria  may  develop 
pathogenic  properties  in  the  manner  indicated, 
seems  extremely  probable ;  and  we  should  a  priori 
expect  that  such  a  result  would  occur  more 
frequently  in  the  tropics,  where  the  elevated 
temperature  and  abundance  of  organic  pabulum 


BACTERIA  IN   INFECTIOUS  DISEASES.  253 

furnish  the  favorable  conditions  required.  In  this 
way  we  may,  perhaps,  explain  the  origin  of  epi- 
demics of  pestilential  diseases,  such  as  yellow  fever 
and  cholera.  If  these  diseases  do  not,  at  the  pres- 
ent day,  originate  in  the  manner  indicated,  they 
at  all  events  have  their  permanent  abiding  place 
in  tropical  countries.  Although  the  specific  germs 
of  these  diseases  have  not  been  demonstrated, 
there  is  strong  reason  for  believing  that  they  re- 
sult from  the  direct  or  indirect  action  of  living 
ferments.  For  there  is  abundant  evidence  to 
prove  that  the  specific  poisons  to  which  they  are 
due  may  multiply  indefinitely  external  to  the  bodies  of 
the  sick.  Such  multiplication  is  a  property  of  liv- 
ing matter  only.  Moreover,  the  conditions  which 
favor  this  multiplication  —  an  elevated  tempera- 
ture and  the  presence  of  decomposing  organic 
material  —  are  exactly  the  conditions  required  for 
the  development  of  low  organisms. 

The  experimental  transformation  of  the  harm- 
less hay-bacillus  (B.  subtilis)  into  the  deadly  Ba- 
cillus anihracis  has  been  claimed  by  Buchner  and 
by  Xageli ;  and  Prof.  Greenfield  claims  to  have 
transformed,  by  a  series  of  culture  experiments, 
the  anthrax  bacillus  into  a  harmless  form  not  dis- 
tinguishable from  the  hay  bacillus.  Koch  insists, 
however,  that  these  are  distinct  species,  and  the 
weight  of  evidence  seems  to  be  in  favor  of  this 
view.  However  this  may  be,  it  is  beyond  ques- 
tion that  the  anthrax  bacillus  may  undergo  a  re- 
markable modification  as  regards  virulence;  and 


254  BACTERIA  IN  INFECTIOUS  DISEASES. 

Pasteur  asserts  that  this  virulence  may  be  restored 
by  inoculating  guinea-pigs  but  a  day  old,  which 
succumb  to  this  attenuated  virus,  although  those 
which  are  five  or  six  days  old  are  proof  agains  it. 
After  several  successive  inoculations,  older  guinea- 
pigs  are  killed,  and  after  a  time  the  virus  becomes 
sufficiently  potent  to  destroy  a  full-grown  animal. 
Finally  it  regains  its  full  activity,  and  will  kill  a 
sheep. 

The  form  of  induced  septicaemia  in  the  rabbit, 
which  has  been  especially  studied  by  the  writer 
(see  p.  355),  furnishes  a  good  example  of  an  in- 
fectious disease  resulting  in  one  species  of  animal 
from  the  introduction  into  its  body  of  a  micro- 
organism which  is  harmless  for  other  species. 
This  organism  —  a  micrococcus  —  is  commonly 
found  in  normal  human  saliva,  where  it  is  asso- 
ciated with  various  other  species.  Experiments 
thus  far  made  indicate  that  there  are  various 
physiological  varieties  (breeds)  of  this  micrococ- 
cus, varying  in  pathogenic  power ;  for  the  saliva 
of  different  individuals  differs  in  virulence.  This 
may  be  accounted  for  by  the  fact  that  the  con- 
ditions are  not  identical.  The  human  mouth  is  a 
culture-apparatus  in  which  the  conditions  are  ex- 
tremely favorable  for  the  development  of  these 
minute  plants;  the  secretions  from  the  salivary 
glands  afford  a  constant  supply  of  pabulum,  and 
the  temperature  is  maintained  at  a  fixed  point. 
But  the  flow  of  saliva  is  more  abundant  in  some 
persons  than  in  others;  and  the  presence  of  de- 


BACTERIA  IN  INFECTIOUS  DISEASES.  2 -JO 

cayed  teeth  and  of  organic  material,  from  neglect 
of  the  tooth-brush,  may  favor  the  development  of 
putrefactive  bacteria,  which  are  fatal  to  the  spe- 
cies of  micrococcus  which  produces  septicaemia  in 
rabbits.  Differences  in  habit  as  to  the  expectora- 
tion of  the  saliva  or  retaining  it  in  the  oral  cavity, 
and  as  to  breathing  through  the  nose  or  through 
the  mouth,  will  also  constitute  differences  in  the 
environment  of  the  micrococcus  which  can  scarcely 
fail  to  have  an  influence  upon  its  physiological 
characters.  When  the  flow  of  saliva  is  rapid,  and 
it  is  not  long  retained  in  the  mouth,  it  is  evident 
that  an  organism  which  multiplies  rapidly  will 
have  the  advantage  of  one  which  multiplies  slowly 
and  may  survive  where  the  other  would  quickly 
disappear.  There  will  also  be  a  constant  ten- 
dency to  develop  still  further  this  capacity  for 
rapid  multiplication,  which  no  doubt  is  an  impor- 
tant, if  not  the  essential,  factor  in  giving  to  a 
micro-organism  pathogenic  power.  The  impor- 
tance of  this  factor  will  be  appreciated  when  we 
remember  that  one  method  by  which  nature  limits 
the  power  for  mischief  of  putrefactive  bacteria 
injected  into  the  tissues  is  by  a  conservative 
inflammatory  process,  which  builds  a  wall  about 
the  invading  parasites,  and  confines  their  depreda- 
tions within  the  narrow  limits  of  an  abscess.  In 
the  disease  produced  by  inoculation  with  saliva,  or 
with  a  culture-fluid  containing  the  micrococcus 
under  consideration,  owing  perhaps  to  the  rapid 
development  of  the  micrococcus,  no  such  limiting 


256  BACTERIA  IN  INFECTIOUS   DISEASES. 

wall  of  inflammatory  exudation  is  established ; 
and  we  find  the  subcutaneous  connective  tissue 
diffusely  infiltrated  with  serum  which  swarms 
with  the  parasite. 

The  failure  to  restrict  the  inroads  of  the  para- 
site may  not  be  due  alone  to  its  power  of  rapid 
multiplication.  It  is  not  improbable  that  some 
poison  is  produced,  during  its  active  growth,  which 
lowers  the  vital  resistance  of  the  tissues  and  pre- 
vents the  occurrence  of  conservative  adhesive  in- 
flammation. And  it  may  be  that  the  true  expla- 
nation of  the  immunity  afforded  by  a  mild  attack 
of  an  infectious  germ-disease  is  to  be  found  in  an 
acquired  tolerance  to  the  action  of  a  chemical  poi- 
son produced  by  the  micro-organism,  and  conse- 
quent ability  to  bring  the  resources  of  nature  to 
bear  to  restrict  invasion  by  the  parasite. 

In  the  infectious  disease  known  as  hospital  gan- 
grene, circumstances  relating  to  the  origin,  nature, 
and  treatment  of  the  malady  make  it  seem  ex- 
tremely probable  that  some  species  of  bacterium, 
ordinarily  harmless,  develops  pathogenic  proper- 
ties as  the  result  of  an  unusually  favorable  environ- 
ment, and  becomes  the  infecting  agent,  which,  by 
invading  the  enfeebled  tissues,  causes  the  rapidly 
extending  necrosis  which  is  characteristic  of  this 
frightful  malady.  This  disease  is  developed  de  novo 
in  the  surgical  wards  of  hospitals,  where  numerous 
patients,  with  profusely  discharging  wounds,  are 
brought  together.  Like  its  congeners,  erysipelas 
;iiid  puerperal  fever,  it  is  prevented  by  cleanliness 


BACTERIA  IN  INFECTIOUS  DISEASES.  207 

and  antiseptic  treatment.  Its  progress  cannot, 
however,  be  arrested  by  ordinary  antiseptic  appli- 
cations ;  for  the  pathogenic  organism  (hypothetical 
as  yet)  invades  the  tissues  to  a  certain  depth,  and 
its  destruction  requires  something  more  than  a 
superficial  germicide  action,  —  e.  g.,  bromine,  nitric 
acid,  the  hot  iron. 

Diphtheria,  also,  is  a  disease  in  which  there  seems 
to  be  good  reason  for  believing  that  the  different 
degrees  of  virulence  are  due  to  circumstances  re- 
lating to  the  genealogy  of  the  infecting  organism, 
as  well  as  to  the  resisting  power  of  the  infected 
individual ;  and  that,  as  in  anthrax  and  in  fowl- 
cholera,  physiological  varieties  of  the  pathogenic 
micrococcus,  to  which  this  disease  is  probably  due, 
may  be  developed  by  special  conditions  relating  to 
its  environment,  either  in  the  fauces  of  an  infected 
individual  or  external  to  the  human  body. 

It  is  not  alone  by  invading  the  blood  or  tissues 
that  bacteria  exhibit  pathogenic  power.  Chemical 
products  evolved  during  their  vital  activity,  ex- 
ternal to  the  body,  or  in  abscesses  and  suppurating 
wounds,  or  in  the  alimentary  canal,  may  doubtless 
be  absorbed  and  exercise  an  injurious  effect  upon 
the  animal  economy.  Indeed,  we  have  experi- 
mental evidence  that  most  potent  poisons  are  pro- 
duced during  the  putrefactive  decomposition  of 
organic  matter.  The  poisons,  resembling  the  vege- 
table alkaloids  in  their  reactions,  called  ptomaines 
by  Selmi,  who  first  obtained  them  from  a  cadaver, 
are  fatal'  to  animals  in  extremely  minute  doses. 

17 


258  BACTERIA  IN  INFECTIOUS  DISEASES. 

These  ptomaines  have  also  been  obtained  by  Gau- 
tier  from  putrid  blood  and  from  the  normal  secre- 
tions of  healthy  persons,  —  saliva,  urine,  blood, 
etc. 

The  soluble  poison,  sepsin,  which  has  been 
shown  by  the  researches  of  Bergmann,  Panum, 
Burdon  Sanderson,  and  others,  to  exist  in  putrid 
blood  is  fatal  to  animals  when  administered  in  a 
sufficient  dose,  which,  however,  is  very  small. 
According  to  Koch  five  drops  of  blood,  which  has 
not  putrefied  too  long,  is  sufficient  to  kill  a  mouse 
within  a  short  time.  After  receiving  an  injection 
of  this  kind  the  symptoms  of  poisoning  are  de- 
veloped immediately r,  and  the  animal  dies  in  from 
four  to  eight  hours. 

"  In  such  a  case  the  greater  part  of  the  fluid  injected 
is  found  in  the  subcutaneous  cellular  tissue  of  the  back 
in  much  the  same  condition  as  before  it  was  injected. 
It  contains  bacteria  of  the  most  diverse  forms,  irregularly 
mixed  together,  and  as  numerous  as  when  examined 
before  injection.  No  inflammation  can  be  observed  in 
the  neighborhood  of  the  place  of  injection.  The  inter- 
nal organs  are  also  unaltered.  If  blood  taken  from  the 
right  auricle  be  introduced  into  another  mouse,  no  effect 
is  produced.  Bacteria  cannot  be  found  in  any  of  the 
internal  organs  or  in  the  blood  of  the  heart. 

"  An  infective  disease  has  therefore  not  been  produced 
as  the  result  of  the  injection.  On  the  other  hand,  there 
can  be  no  doubt  that  the  death  of  the  animal  was  due 
to  the  soluble  poison,  sepsin. 

"  This  supposition  is  confirmed  by  the  fact' that  when 


BACTERIA  IN  INFECTIOUS  DISEASES.  259 

less  fluid  is  introduced  into  the  animal  the  symptoms  of 
poisoning  which  follow  are  less  marked,  and  are  quite 
absent  when  one  or  at  most  two  drops  have  been  in- 
jected." l 

On  the  other  hand,  the  infectious  disease  which 
results  in  certain  cases  from  a  similar  inoculation 
produces  death  only  at  the  end  of  forty  to  sixty 
hours,  and  is  attended  with  definite  pathological 
lesions  and  the  presence  of  a  minute  bacillus  in 
the  blood  and  tissues  of  the  infected  animal.  A 
very  small  quantity  (e.  g.,  one-tenth  of  a  drop)  of 
the  fluid  of  the  subcutaneous  oedema,  or  of  blood 
from  the  heart  of  such  an  animal,  is  sufficient  to 
infect  another,  and  Koch  has  fully  demonstrated 
the  infectious  nature  of  the  disease  by  a  series  of 
seventeen  successive  inoculations.  He  says :  "  It 
is  sufficient,  in  order  to  bring  about  the  death  of 
the  animal  in  about  fifty  hours,  to  pass  the  point 
of  a  small  scalpel,  which  has  been  in  contact  with 
the  infected  blood,  over  a  small  wound  in  the  skin." 

This  distinction  between  septic  toxaemia  and  in- 
fectious septicaemia,  which  has  been  established  by 
the  experimental  researches  of  Koch,  Pasteur,  and 
many  others,  is  opposed  to  the  results  reported  by 
Rosenberger  of  Wurzburg,  who  claims  to  have 
demonstrated  that  the  various  forms  of  septic 
micro-organisms  appear  in  the  body  of  an  animal 
which  has  been  subjected  to  experimental  inocula- 
tion, not  because  like  organisms  have  been  intro- 

1  Traumatic  Infectious  Diseases,  Sydenham  Society's  translation, 
London,  1880,  p.  35. 


260  BACTERIA  IN  INFECTIOUS  DISEASES. 

duced  as  seed,  but  as  a  result  of  the  introduction 
of  a  chemical  poison  which  causes  organisms  pre- 
viously present  in  the  body  of  the  animal  to  make 
their  appearance  in  the  blood,  etc. 

That  the  injection  of  sepsin  favors  the  develop- 
ment of  bacteria  introduced  at  the  same  time  is 
very  probable,  and  we  cannot  help  believing  that 
Kosenberger  has  unwittingly  introduced  living 
bacteria  with  his  cooked  septic  blood  and  serum, 
notwithstanding  the  precautions  which  he  claims 
to  have  taken.  This  view  is  supported  by  the  ex- 
periments of  Zuelzer  and  Sonnenschein,  who, 
finding  a  resemblance  between  the  physiological 
effects  of  sepsin  and  of  atropia,  injected  two  to 
five  centigrammes  of  neutral  sulphate  of  atropia 
at  the  same  time  with  a  culture-solution  contain- 
ing bacteria.  Fatal  septicaemia  was  found  to  re- 
sult from  these  inoculations,  while  the  bacteria 
injected  alone  did  no  harm. 

The  subcutaneous  injection  of  other  potent  poi- 
sons has  been  found  to  be  followed  by  local  necro- 
sis and  rapidly  developed  putrefactive  changes ; 
but  there  is  reason  to  believe  th&t  in  these  in- 
stances, also,  the  putrefactive  germs  are  intro- 
duced simultaneously  with  the  chemical  poison,  or 
find  their  way  through  the  inoculation  wound  from 
the  exterior,  rather  than  to  suppose  that  they  are 
developed  within  the  body  of  the  animal.  For 
the  observations  and  experiments  of  numerous 
investigators  are  opposed  to  the  belief  that  bacte- 
ria are  habitually  present  in  the  blood  and  tissues 


BACTERIA  IN  INFECTIOUS  DISEASES.  261 

of  living  animals.  They  are  known  to  infest  the 
alimentary  canal,  and  it  is  probable  that  the  small- 
est portion  of  hair  or  epithelium  detached  from 
the  surface  of  the  body  of  any  one  of  the  lower 
animals  would  fertilize  a  culture-solution ;  but 
blood  drawn  from  the  veins  with  proper  precau- 
tions does  not  fertilize  a  sterilized  culture-solution. 
Koch  sa3^s  (/.  c.)  "  I  have  on  many  occasions  exam- 
ined normal  blood  and  normal  tissues  by  means 
which  prevent  the  possibility  of  overlooking  bac- 
teria, or  of  confounding  them  with  granular  masses 
of  equal  size;  and  I  have  never,  in  a  single  in- 
stance, found  organisms.  /  hare,  therefore,  come  to 
the  conclusion  ihat  bacteria  do  not  occur  in  the  Hood,  nor 
in  the  tissues  of  the  hcatthy  living  body,  either  of  man  or 
of  the  lower  animals." 

As  an  example  of  the  development  of  putre- 
faction, as  a  result  of  inoculation  by  a  chemical 
virus,  we  may  refer  to  the  recent  experiments  of 
Weir  Mitchell,  and  Reichert,  "  On  the  Venom  of 
Serpents."  These  gentlemen  find  that  venom 
contains  three  proteids.  One  of  these,  venom 
peptone,  is  not  poisonous  as  a  venom,  but  its  in- 
jection into  the  breast  of  a  pigeon  gives  rise  to 
remarkable  local  effects.  A  lump  forms,  and  with- 
in forty-eight  hours  a  gangrenous  cavity  is  pro- 
duced, from  which  putrefactive  odors  are  given  off. 
That  putrefaction  here,  as  elsewhere,  is  produced 
by  the  bacteria  of  putrefaction,  there  can  be  no 
doubt ;  for  no  known  proteid  is  capable  of  pro- 
ducing putrefactive  changes  in  a  sterilized  organic 


262  BACTERIA  IN  INFECTIOUS  DISEASES. 

fluid ;  and  that  the  bacteria  of  putrefaction  were 
introduced  from  without,  is  likewise  altogether 
probable,  inasmuch  as  we  have  no  account  of 
special  precautions  having  been  taken  to  exclude 
these  ubiquitous  organisms,  and  in  view  of  what 
has  just  been  said  as  to  their  absence  from  the 
blood  and  tissues  of  healthy  animals. 

Panum  found  that  a  putrid  solution  boiled  for 
eleven  hours  still  produces  symptoms  of  putrid 
poisoning,  and  that  when  such  a  fluid  is  evapo- 
rated to  dryness,  and  the  residue  extracted,  first 
with  alcohol  and  then  with  water,  the  alcoholic 
extract  does  not  produce  the  symptoms,  while  the 
watery  extract  does.  There  can  be  little  doubt 
that  the  watery  extract  injected  contained  living 
bacterial  germs,  not  from  the  putrid  fluid  operated 
upon,  but  in  the  water  used  for  making  the  ex- 
tract (cold),  in  the  syringe  used  for  injecting  it,  or 
possibly  carried  from  the  surface  of  the  body  of 
the  animal  by  the  point  of  the  needle  used  in 
making  the  injection.  According  to  this  explana- 
tion, germs  introduced  in  the  way  indicated  would 
multiply  and  produce  putrefactive  decomposition 
because  the  vitality  of  the  tissues  was  reduced  or 
destroyed  by  the  chemical  poison;  whereas  if  intro- 
duced alone,  even  in  vastly  greater  numbers,  they 
could  do  no  harm,  owing  to  the  vital  resistance  of 
the  tissues.  The  writer  has  frequently  injected 
culture-fluids  containing  the  bacteria  of  putrefac- 
tion beneath  the  skin  of  a  rabbit,  without  serious 
result.  But  the  smallest  drop  of  fluid  containing 


BACTERIA  IN  INFECTIOUS  DISEASES.  263 

the  oval  micrococcus,  which  produces  infectious 
septicaemia  in  rabbits,  produces  a  fatal  result  with- 
in forty-eight  hours ;  and  the  virulence  of  blood, 
or  of  a  culture-fluid  containing  this  micrococcus  or 
the  anthrax  bacillus  (without  spores),  is  destroyed 
by  exposure  for  ten  minutes  to  a  temperature  of 
140*  Fahr.?  whereas  sepsin,  the  ptomaines,  and 
serpent  virus  —  venom  glohiline  —  all  withstand  a 
boiling  temperature. 

In  the  pages  which  follow,  the  writer  proposes 
to  pass  in  review  the  infectious  diseases  which, 
upon  evidence  more  or  less  convincing,  have  been 
supposed  to  depend  upon  the  invasion  of  the  in- 
fected animal  by  a  parasitic  micro-organism.  The 
limits  of  the  present  volume  will,  however,  only 
admit  of  a  brief  resume  of  the  observations  and 
experimental  evidence  bearing  upon  this  suppo- 
sition, for  each  disease  in  the  list ;  and  the  reader 
who  desires  fuller  information,  is  referred  to  the 
copious  bibliography  appended.  For  convenience 
of  reference,  the  diseases  are  arranged  alphabeti- 
cally. 


PLATE  VII. 

FIG.  1.  —  Blood  of  guinea-pig  dead  of  symptomatic  anthrax. 
Blood-corpuscles,  and  between  them  several  bacilli.  X  700.  (From 
The  Practitioner,  London,  June,  1884,  p.  426.  Klein.) 

FIG.  2.  —  Blood  of  guinea-pig  dead  of  Koch's  malignant  oedema. 
1.  red  blood  discs  ;  2.  white  corpuscles  ;  3.  single  bacilli  ;  4.  chain 
of  long  bacilli ;  5.  leptothrix.  X  700.  (From  The  Practitioner, 
London,  June,  1884,  p.  424.  Klein.) 

FIG.  3.  —  Spirochcete  Obc.rmeieri.  X  700.  (From  a  photo-micro- 
graph by  Koch.) 

FIG.  4.  —  Bacilli  from  the  pericardial  serum  of  a  corpse,  ob- 
tained three  days  after  death,  in  summer.  X  700.  (From  a  photo- 
micrograph by  Koch.) 


PLATE  Vll. 


Fijf.l 


Fitf  2 


' 


ANTHRAX.  265 


INFECTIOUS  DISEASES  WHICH  HAVE  BEEN  AS- 
CRIBED TO  THE  PRESENCE  OF  BACTERIA. 


ANTHRAX  ;  Charbon,  Fr.,  Mtttzbrcmd,  Ger.  — 
This  is  an  infectious  disease  of  animals  which  may 
be  transmitted  to  man  by  inoculation.  This  occurs, 
occasionally,  from  the  bite  of  an  insect  (fly)  which 
has  been  feeding  upon  the  carcass  of  an  infected 
animal ;  and  also  from  accidental  inoculation  while 
handling  hides,  wool,  etc.,  taken  from  the  victims 
of  anthrax. 

The  herbivora  are  most  susceptible  to  anthrax ; 
and  in  certain  parts  of  Europe  the  annual  losses 
from  this  disease,  among  the  herds  and  flocks  of 
the  farmers,  are  very  considerable. 

The  susceptibility  of  the  carnivora  to  this  and 
other  forms  of  septicaemia  is  very  much  less  than 
that  of  the  herbivora.  This  difference  is  probably 
due  to  natural  selection ;  for  the  bodies  of  herbiv- 
orous animals,  dead  from  anthrax,  have  doubtless 
been  devoured  by  the  carnivora  from  the  earliest 
times  (anthrax  was  known  to  the  Greek  and  Koman 
physicians) ;  and,  although  inoculation  is  not  liable 
to  occur  through  the  uninjured  mucous  membrane 
of  the  mouth,  or  of  the  intestine,  it  could  scarcely 
fail  to  occur  as  a  result  of  wounds  inflicted  by  the 
teeth  and  claws  of  the  contestants  for  the  infected 


266  BACTERIA  IN  INFECTIOUS  DISEASES. 

prey.  An  individual  difference  in  susceptibility  to 
the  poison,  and  the  survival  of  the  fittest,  would 
in  time  be  very  sure  to  produce  a  race  immunity. 
This  view  is  not,  however,  sustained  by  the  ex- 
periments of  Prof.  Feser  upon  rats.  In  these 
experiments  it  was  found  that  rats  fed  on  flesh 
do  not  contract  anthrax,  but  that  the  same  rats 
when  restricted  to  a  vegetable  diet  fall  victims 
to  the  disease  after  inoculation  with  anthrax 
fluids. 

The  immunity  of  fowls  has  been  proved  by 
Pasteur  to  be  a  question  of  temperature.  Accord- 
ing to  Chauveau,  multiplication  of  the  bacillus  in 
culture-fluids  ceases  at  43°.  This  is  but  little  above 
the  normal  temperature  of  the  fowl.  If,  however, 
the  temperature  is  reduced  two  or  three  degrees 
by  immersing  the  lower  part  of  its  body  in  cold 
water,  the  fowl  becomes  susceptible  and  dies  as 
the  result  of  inoculation  with  a  fluid  containing 
the  bacillus. 

The  anthrax  bacillus  is  said  to  have  been  ob- 
served by  Pollender  in  the  blood  of  cattle  as  early 
as  1849,  and  by  Davaine  in  1850.  But  the  etio- 
logical  importance  of  the  parasite  was  first  recog- 
nized by  the  last  named  observer,  and  was  affirmed 
in  a  series  of  communications  to  the  French 
Academy,  made  in  1863  and  1864.  The  experi- 
ments of  Davaine  established  the  fact  of  the 
presence  of  rod-shaped  bacteria  in  the  blood  of 
animals  attacked  with  charbon,  and  that  a  healthy 
animal  into  which  a  small  quantity  of  this  blood  is 


ANTHRAX.  267 

injected  quickly  succumbs  to  the  disease,  its  blood 
also  being  invaded  by  the  parasite. 

The  view  that  the  infectious  properties  of  an- 
thrax blood  depend  upon  the  presence  of  this 
parasite  was  strongly  contested,  and  since  Da- 
vaine's  first  experimental  inoculations,  a  host  of 
investigators  have  entered  the  field.  The  question 
is  admitted  by  all  to  be  of  the  greatest  importance, 
and  has  been  most  thoroughly  investigated  by  the 
experimental  method,  every  point  made  by  those 
in  favor  of  the  parasitic-germ  theory  having  been 
stoutly  contested  by  conservative  opponents.  The 
literature  of  the  subject,  although  so  recent,  is 
very  voluminous;  and  the  fact  that  the  anthrax 
bacillus  is  the  essential  infectious  element  in  an- 
thrax blood,  and  that  the  disease  anthrax  is  due  to 
the  multiplication  of  this  parasite  in  the  body  of 
an  infected  animal,  has  been  established  in  the 
face  of  the  most  exacting  scientific  criticism. 

Klebs  first  showed  that  anthrax  blood  loses  its 
infectious  properties  after  filtration,  while  the  fil- 
trate is  virulent ;  but  as  other  solid  elements 
(fibrine  and  globules)  were  retained  as  well  as  the 
bacilli,  this  was  not  accepted  as  proof  that  the 
latter  were  the  essential  infectious  particles. 

This  proof  has  been  furnished  by  inoculation 
experiments  with  pure-cultures  of  the  anthrax 
bacillus,  which  have  now  been  made  by  numerous 
experimenters  in  various  parts  of  the  world.  By 
successive  cultures,  in  which  a  small  amount  of 
material  is  used  to  inoculate  a  considerable  quan- 


268  BACTERIA  IN  INFECTIOUS  DISEASES. 

tity  of  the  culture-fluid,  we  soon  exclude  all  non- 
living particles,  and  soluble  substances  as  well, 
contained  in  the  material  introduced  as  seed  into 
culture  No.  1  (see  remarks  on  p.  238). 

In  such  a  series,  which  has  been  carried  as  far 
as  the  one-hundredth  successive  culture  (Pasteur), 
the  virulence  of  the  last  culture-fluid  is  as  great  as 
that  of  the  first ;  and,  as  the  culture-fluid  itself  is 
innocuous,  this  virulence  can  be  ascribed  only  to 
the  living  bacilli  contained  in  it,  which  are  the 
direct  descendants  of  those  present  in  the  minute 
drop  of  anthrax  blood  used  to  inoculate  culture 
No.  1. 

Experiments  of  this  kind  are  conclusive  as  to 
the  essential  etiological  role  of  the  anthrax  bacil- 
lus, but  they  do  not,  of  course,  explain  its  modus 
operandi.  Pasteur  has  shown  that  the  bacillus  is 
aerobic,  —  i.e.,  that  its  development  depends  upon 
the  presence  of  oxygen,  —  and  there  can  be  no 
doubt  that,  during  its  rapid  multiplication  in  the 
blood  of  a  living  animal,  it  deprives  this  fluid  of 
its  oxygen,  and  also  of  other  constituents  required 
for  its  own  nutrition.  The  deprivation  of  oxygen 
is  shown  by  the  symptoms,  —  dyspnoea,  cyanosis, 
depressed  temperature,  and  finally  death,  with  all 
the  symptoms  of  asphyxia.  It  also  acts  mechan- 
ically, by  blocking  up  the  capillaries,  and  pro- 
ducing emboli  and  hemorrhagic  extravasation  in 
various  parts  of  the  body.  In  addition  to  this,  we 
have  evidence  that,  as  in  other  forms  of  septicae- 
mia, a  potent  chemical  poison  is  produced  as  a  re- 


ANTHRAX.  269 

suit  of  vital  processes  connected  with  the  nutrition 
of  the  bacillus.  Paul  Bert  has  been  able  to  isolate 
a  poison,  diffusible  in  liquid,  which  kills  in  twelve 
hours.  This  he  accomplished  by  destroying  the 
bacillus  in  a  fluid  containing  it  by  means  of  com- 
pressed oxygen.  Toussaint,  also,  by  injecting  fil- 
tered anthrax  blood,  obtained  evidence  of  the 
presence  in  it  of  a  poison  which,  in  his  experi- 
ments, produced  only  a  local  inflammation,  with- 
out any  noticeable  constitutional  symptoms. 

The  discovery,  which  we  owe  to  Koch,  that, 
under  favorable  conditions,  the  anthrax  bacillus, 
either  in  culture-fluids  or  in  the  body  of  a  dead 
animal,  develops  refrangant,  endogenous  spores, 
which  have  great  resisting  power  against  heat  and 
chemical  reagents,  and  may  be  preserved  for  years 
without  loss  of  vitality,  has  enabled  us  to  account, 
in  a  most  satisfactory  manner,  for  certain  facts 
which  previously  seemed  to  be  irreconcilable  with 
a  belief  in  the  parasitic-germ  theory.  Thus  Bert 
treated  anthrax  blood,  which  he  had  received  from 
Alfort,  with  three  times  its  volume  of  absolute 
alcohol,  then  washed  the  coagulum  in  alcohol,  and 
dried  it  in  vacuo.  This  material,  mixed  with  water 
and  again  precipitated  by  alcohol,  proved  to  be 
virulent  when  injected  into  guinea-pigs.  Even 
after  remaining  for  five  months  immersed  in  alco- 
hol, this  virus  had  not  lost  its  potency. 

These  facts  were  explained  by  Pasteur,  and,  in  a 
subsequent  communication,  Bert  himself  explained 
the  mystery.  Further  experiments  had  convinced 


270  BACTERIA  IN  INFECTIOUS  DISEASES. 

him  that  virulent  fluids  containing  anthrax  rods 
did  not  resist  either  alcohol  or  compressed  oxy- 
gen, and  that  it  was  only  when  reproductive  spores 
were  present  that  the  ftakes  of  material  precipi- 
tated by  alcohol  gave  evidence  of  virulence.  Upon 
microscopical  examination  these  shining  spores 
were  detected  in  the  flakes  in  question,  and  their 
continued  vitality  after  the  treatment  indicated 
was  proved  by  their  germination  in  a  culture- 
fluid. 

The  anthrax  rods  are  killed  by  ten  minutes'  ex- 
posure to  a  temperature  of  54°  C.  (129°. 2  Fahr.), 
by  desiccation,  and  by  putrefaction  of  the  fluid  con- 
taining them,  in  the  absence  of  oxygen ;  but  the 
resting-spores  resist  prolonged  boiling  (Pasteur), 
and  are  not  injuriously  affected  by  desiccation  or 
by  putrefaction.  Spores  are  not  formed  in  the 
rods  as  they  are  found  in  the  body  of  a  living 
animal;  but  after  death,  under  favorable  circum- 
stances, these  rods  grow  into  filaments  in  the  in- 
terior of  which  shining  oval  bodies  are  developed, 
which  are  the  spores  in  question.  Thus  the  car- 
cass of  a  dead  animal  may  become  a  storehouse  of 
anthrax  seed,  which  may  for  many  years  after  its 
death  infect  pastures  in  which  the  animal  was 
buried.  But  no  development  of  spores  occurs  in 
the  absence  of  oxygen ;  and  under  these  circum- 
stances the  rods  quickly  disintegrate  and  disap- 
pear. This  is  shown  by  enclosing  in  a  tightly 
corked  bottle  blood  from  an  animal  recently  dead. 
Putrefactive  decomposition  soon  takes  place,  but 


ANTHRAX.  271 

the  blood  loses  its  virulence,  and  neither  rods  nor 
spores  can  be  discovered  in  it  after  a  few  days. 

According  to  Ewart,  when  cultivated  upon  a 
warm  stage  in  albuminous  fluids,  the  anthrax  rods 
become  motile  within  a  few  hours,  and  exhibit  al- 
ternations of  motion  and  quiescence.  This  does 
not  correspond  with  the  observations  of  Koch,  and 
is  probably  a  mistake.  Magnin,  on  page  88  of  the 
present  volume,  in  giving  the  specific  characters 
of  B.  anthracis,  states  that  it  is  always  motionless. 
If  the  temperature  is  maintained  at  about  33°  C. 
(91.4°  Fahr.)  the  rods  soon  grow  into  long  homo- 
geneous filaments,  which  in  the  course  of  four  or 
five  hours  may  reach  a  length  many  times  greater 
(50-100  times)  than  the  original  bacilli.  These 
are  often  twisted  and  interlaced  in  the  culture- 
fluid.  A  little  later  the  filaments,  which  were  at 
first  hyaline,  are  seen  to  consist  of  a  distinct 
sheath  and  a  central  cylinder  of  protoplasm,  which 
soon  undergoes  segmentation,  each  segment  being 
about  the  length  of  the  original  rods.  The  spores 
are  formed  by  a  consolidation  of  the  protoplasm 
of  one  of  these  segments  into  an  oval  mass,  which 
is  subsequently  set  free  by  rupture  of  the  cellular 
envelope,  or  by  its  granular  disintegration.  The 
oval  shining  spores  after  their  escape  present  the 
appearance  of  being  enclosed  in  a  gelatinous  en- 
velope, which  according  to  Koch,  is  developed 
into  a  new  rod  when  germination  takes  place. 
Other  observers  (Ewart,  Cohn)  assert  that  the 
central  protoplasm  is  developed  into  a  new  rod, 


PLATE   VIII. 

Bacillus  Anthracis. 

FIG.  1.  —  Anthrax  bacillis  in  spleen-pulp  of  rabbit,  just  dead 
from  an  experimental  inoculation  made  two  days  previously.  The 
spherical  bodies  are  splenic  corpuscles.  Stained  with  Bismark 
brown.  X  250  diameters. 

FIG.  2.  —  Anthrax  bacillis  in  liver  of  the  same  rabbit ;  same 
staining  and  amplification. 

FIG.  3.  —  Spore-bearing  filament  of  B.  anthracis,  from  culture  in 
chicken  bouillon.  Scattered  spores,  and  fragments  of  filaments 
which  had  broken  up  without  producing  spores,  are  also  seen. 
X  500  diameters.  Methyl-violet  staining. 

FIG.  4.  —  B.  anthracis  in  culture-solution  (beef-peptone)  in- 
oculated twelve  hours  previously  with  material  shown  in  Fig.  1 
(spleen-pulp  containing  rods).  X  250  diameters.  Bismark  brown 
staining. 

FIG.  5.  —  B.  anthracis  in  glomerulus  of  kidney  of  same  rabbit  as 
furnished  material  for  Figs.  1  and  2.  X  250  diameters.  Bismark 
brown  staining. 


PLATE  vm. 


V     *Ws'»>'J^ 
'''•Jh£&<m£f*4i 


FIG.    i. 


FIG.   2, 


FIG.  3. 


FIG.  4. 


FIG.  5. 


ANTHRAX.  273 

and  that  the  envelope  is  used  up  during  its 
growth. 

At  35°  C.  (95°  Fahr.)  spores  make  their  ap- 
pearance at  the  end  of  twenty-four  hours.  At  a 
lower  temperature  (28°  C.)  the  growth  of  the  rods 
into  filaments  takes  place  more  slowly,  and  the 
formation  of  spores  is  not  completed  in  less  than 
thirty-six  to  forty-eight  hours.  At  42°  to  43°  C. 
the  rods  grow  and  multiply  by  fission,  but  spores 
are  no  longer  formed.  No  development  occurs 
at  temperatures  below  12°  C.  (53.6°  Fahr.).  In 
Fig.  3,  Plate  VIII.,  a  spore-bearing  filament  is 
seen  in  the  centre  of  the  field,  while  scattered 
about  are  liberated  spores  and  detached  segments 
of  the  filaments.  The  amplification  is  500  diame- 
ters, and  the  specimen  is  from  a  culture  made 
in  chicken  bouillon. 

A  statement  relating  to  the  source  of  the  ma- 
terial which  furnished  specimens  for  my  photo- 
micrographs, Plate  VIII.,  may  not  be  uninterest- 
ing, as  illustrating  the  facts  already  given. 

While  pursuing  certain  experimental  inquiries 
in  the  biological  laboratory  of  Johns  Hopkins 
University  during  the  summer  of  1881,  Professor 
Martin  placed  in  my  hands  a  small  tube  just  re- 
ceived by  him  from  Dr.  Burdon-Sanderson,  of 
London.  In  a  letter  accompanying  this,  Burdon- 
Sanderson  says:  "I  send  you  the  material  I 
started  from  in  the  last  experiments  I  made  upon 
the  subject  (anthrax).  It  was  then  five  years 
old,  and  consequently  is  now  seven  or  eight.  I 


274  BACTERIA  IN  INFECTIOUS  DISEASES. 

have  no  doubt  that  you  will  find  that  if  worked 
up  with  salt-solution  and  injected  into  a  mouse, 
you  will  have  the  spleen  —  after  from  twenty-four 
to  thirty-six  hours  —  enlarged  and  infiltrated  with 
Bacillus."  This  scientific  prediction  was  fulfilled 
to  the  letter.  The  tube  only  contained  a  fraction 
of  a  grain  of  dried  blood.  This  was  rubbed  up 
with  a  little  salt-solution  in  accordance  with  the 
directions  given,  and  a  few  minims  of  the  solution 
injected  beneath  the  skin  of  a  recently-captured 
mouse.  The  animal  died  in  a  little  less  than 
thirty-six  hours,  and  its  liver  and  spleen  contained 
an  abundance  of  bacilli. 

A  portion  of  the  spleen  of  this  animal  was 
placed  in  a  culture-cell  with  a  little  chicken  bouil- 
lon, and  kept  for  twenty-four  hours  in  the  cul- 
ture-oven, at  a  temperature  of  100°  Fahr.  The 
following  day  the  culture-fluid  was  found  to  con- 
tain a  luxuriant  growth  of  filaments,  many  of 
which  contained  shining  oval  spores.  A  fragment 
of  the  spleen  of  the  mouse  was  used  to  inoculate 
a  small  quantity  of  blood  from  a  healthy  rabbit, 
drawn  directly  into  a  sterilized  tube.  The  an- 
thrax bacillus  multiplied  abundantly  in  this  blood, 
growing  into  long  filaments  and  forming  spores, 
as  in  the  culture  in  chicken  bouillon.  On  the  loth, 
two  minims  of  this  blood-culture  were  injected 
into  a  small  rabbit,  and  a  still  smaller  quantity  into 
another  mouse.  The  mouse  died  on  the  following 
day,  and  the  rabbit  on  the  IGth.  Upon  post- 
mortem examination  an  abundance  of  bacilli  were 


ANTHRAX.  275 

found  in  the  blood,  liver,  and  spleen  of  both  these 
animals.  My  only  object  being  to  obtain  a  stock 
of  anthrax  virus,  and  material  from  which  to  make 
some  photo-micrographs  of  Bacillus  anthracis,  the 
experiments  were  not  pursued  any  further  at 
this  time.  Some  dried  blood  was  preserved,  how- 
ever, and  recently  after  an  interval  of  three  years, 
this  was  used  to  inoculate  a  rabbit,  which  died 
on  the  second  day  after,  and  furnished  the  mate- 
rial for  the  photo-micrographs  in  Plate  VIII. 
These  have  been  made  with  a  comparatively  low 
power  in  order  to  show  the  enormous  number  of 
bacilli  in  the  tissues. 

If  we  were  without  satisfactory  experimental 
evidence  that  the  Bacillus  anthracis  is  the  cause  of 
the  disease  anthrax,  we  could  scarcely  suppose  any 
longer  that  its  presence  in  this  disease  is  without 
import,  a  mere  epi-phenomenon,  in  the  face  of 
such  evidence  as  that  given  by  Koch  in  the 
following  extract  from  his  work  on  "  Traumatic 
Infective  diseases"  (Sydenham  Society's  transla- 
tion) :  — 

"  Although  I  had  often  previously  examined  the 
blood  of  animals  suffering  from  anthrax,  and  had  thus 
formed  a  high  estimate  as  to  the  number  of  bacilli  pres- 
ent in  the  body  of  an  anthracic  animal,  yet  I  was  quite 
surprised  when  I  saw  for  the  first  time  sections  and  por- 
tions of  organs  stained  in  this  way  [in  methyl-violet, 
with  carbonate  of  potash,  see  p.  187J,  as  e.g.  the  in- 
testinal mucous  membrane  and  the  iris  of  a  rabbit. 
When  magnified  fifty  diameters,  such  a  preparation 


276  BACTERIA  IN  INFECTIOUS  DISEASES. 

presents,  at  the  first  glance,  an  appearance  as  if  a  blue 
coloring  matter  had  been  injected  into  the  vessels. 
Each  intestinal  villus  is  permeated  by  an  exceedingly 
delicate  blue  net-work  ;  in  the  mucous  membrane  of 
the  stomach  all  the  capillary  net-work  surrounding  the 
gastric  glands  is  stained  blue ;  in  the  ciliary  processes 
each  projection  is  injected,  and  a  spiral  vessel  stained  of 
a  dark  blue  color  leads  from  thence  to  the  iris,  and 
breaks  up  into  a  fine  blue  net-work  with  loops  directed 
towards  the  edge  of  the  iris.  The  liver  and  lungs,  and 
the  glandular  structures,  such  as  the  pancreas  and  sali- 
vary glands,  are  completely  permeated  by  the  same 
blue  capillary  net-work.  Indeed  there  is  no  orpin 
which  is  not  more  or  less  injected  with  the  blue  mass. 
It  is,  however,  very  striking  that  this  injection  is  only 
present  in  the  capillary  vessels.  All  the  larger  vessels, 
even  the  arteries  and  veins  of  an  intestinal  villus,  are 
either  not  stained  at  all  or  have  but  a  light  blue  streak 
in  their  interior,  and  that  only  here  and  there.  When 
magnified  250  times  one  can  see  that  the  blue  capillary 
net-work  is  composed  of  numerous  delicate  rods,  and 
when  a  power  of  700  diameters  is  used,  it  is  found  that 
the  apparent  injection  is  nothing  more  or  less  than  the 
Bacillus  anthraciSi  stained  dark  blue,  and  present  in  in- 
credible numbers  in  the  whole  capillary  system.  In  the 
other  vessels,  especially  in  the  larger  ones,  often  only  a 
single  bacillus  may  be  met  with  at  long  intervals,  or 
they  may  bs  quite  absent.  Here,  therefore,  we  have  a 
striking  proof  of  how  little  value  are  conclusions  drawn 
in  traumatic  infective  diseases  from  the  examination  of 
a  drop  of  blood  taken  from  a  blood-vessel  by  chance ; 
for 'one  might  well  take  a  drop  of  blood  from  the  heart 
and  find  no  micro-organisms  in  it,  or  one  might  readily 
overlook  the  few  which  might  be  present,  and  that 
although  the  capillary  system  abounds  in  these." 


ANTHRAX.  277 

The  results  obtained  by  Pasteur  in  his  experi- 
ments relating  to  protective  inoculations  against 
anthrax,  have  been  of  the  highest  importance,  and 
many  persons  have  been  led  to  share  in  the  san- 
guine expectation  of  the  distinguished  French 
chemist,  that  not  only  in  this  disease,  but  in  the 
infectious  diseases  generally,  protective  inocula- 
tions may  eventually  be  successfully  practised. 
The  various  methods  of  effecting  "  attenuation  of 
virus  "  have  been  described  in  PART  THIRD  of  the 
present  volume. 

Pasteur  recommends,  in  anthrax,  a  double  inoc- 
ulation, first  with  a  greatly  mitigated  virus,  pre- 
mier vacci'n,  and  subsequently  with  a  more  potent 
virus,  denxieme  vaccin.     Whether  in  practice  it  will 
be  found  wise  to  resort  to  protective  inoculations 
rather  than  to  attempt  to  stamp  out  the  disease 
by  the  destruction  of  infected  animals  and  other 
vigorous  preventive  measures,  is  open  to  question. 
As  Klein  has  pointed  out,  the  method  of  Pasteur 
involves  a  multiplication  of  the  poison,  which  may 
add  to  the  danger  of  extensive  losses  occurring 
among  herds  and  flocks  which  have  not  been  pro- 
tected.    Moreover,    there   is    a   certain  mortality 
from  the  application  of  the  method,  and  we  have 
not  yet  learned  how  durable  the  protection  may 
be.     While,  therefore,  we    accord  full   honor  to 
Pasteur  for  his  valuable  contributions  to  science  in 
connection  with  this  interesting  subject,  we  must 
admit  that,  as  a  practical  measure  of  protection, 
the  method  is  still  under  trial.     Koch  is  not  at  all 


278  BACTERIA  IN  INFECTIOUS  DISEASES. 

sanguine  as  to  the  possibility  of  extending  the  ap- 
plication of  the  method  to  other  infectious  diseases, 
and  points  out  that  even  in  anthrax  no  general 
law  of  immunity  has  been  established;  as  several 
observers  (Lceffler,  Gotti,  Guilebeau,  and  Klein) 
have  shown  that  no  such  immunity  is  obtained  in 
the  case  of  guinea-pigs,  rats,  mice,  and  rabbits, 
and  that  thus  far  only  sheep  and  cattle  have  been 
proved  to  acquire  immunity  from  inoculations 
with  attenuated  virus. 

An  interesting  question,  which  has  not  yet  been 
definitely  decided  by  experiment,  relates  to  the 
possible  protection  of  an  animal  which  has  suffered 
an  attack  of  one  form  of  septicaemia  —  e.g.,  an- 
thrax—  from  the  other  allied  forms.  Certainly 
the  infectious  septicaemia  of  rabbits,  due  to  a  mi- 
crococcus,  which  the  writer  has  especially  studied, 
bears  a  strong  resemblance,  in  many  particulars, 
to  anthrax,  and  the  same  may  be  said  of  the  form 
of  septicaemia  in  mice,  due  to  a  minute  bacillus, 
which  has  been  described  by  Koch.  The  question 
is  whether  an  animal  which  has  recovered  from  a 
modified  form  of  one  of  these  diseases  will  not  be 
protected  from  the  others.  If  so,  it  is  extremely 
probable  that  protection  results  from  tolerance  to 
the  chemical  poison  evolved  during  the  growth  ot 
the  micro-organism,  and  consequent  ability  on  the 
part  of  the  tissues  to  withstand  the  attacks  of  the 
parasite,  rather  than  to  the  using  up  of  some  ma- 
terial in  the  body  of  the  animal  which  is  essential 
for  the  development  of  the  microbe.  In  this  case 


ANTHRAX.  279 

the  chemists  are  likely  to  find  that  the  poison 
present  in  the  blood  of  animals  suffering  from 
these  different  forms  of  septicaemia  is  the  same, 
although  the  microbes  differ.  According  to  Pas- 
teur "  there  are  as  many  different  forms  of  septi- 
caemia as  there  are  different  vibrios."  l  And  in  a 
letter  to  his  confrere,  Dumas,  he  says :  "  Numerous 
experiments  have  shown  me  that  cultivation  of 
the  bacteride  (Bacillus  anthracis)  in  a  medium  ex- 
hausted by  the  microbe  of  fowl-cholera,  although 
real,  is  retarded,  not  abundant,  and  difficult.  Con- 
trary to  the  provisions  which  I  have  just  recalled, 
it  may  be,  then,  that  fowls  vaccinated  for  cholera 
are  refractory  to  charbon,  which  is  due  to  a  para- 
site of  quite  a  different  nature.  Such  is  precisely 
the  unexpected  result  which  I  have  obtained  in 
some  experiments  not  yet  sufficiently  numerous 
to  prove  the  fact." 

In  a  later  communication,2  Pasteur  says :  "  It 
may  be  considered  as  established :  First.  That 
chickens  are  refractory  to  charbon.  Second.  That 
chickens,  when  refrigerated,  easily  contract  char- 
bon. Third.  That  chickens  in  which  charbon  is 
established  by  a  lowering  of  temperature,  may  be 
completely  cured  by  warming  them." 

According  to  Arloing,  Cornevin,  and  Thomas, 
immunity  from  anthrax  does  not  protect  from  the 
disease  which  they  have  studied  and  call  symp- 
tomatic anthrax  ;  nor  does  immunity  from  the  latter 
disease  afford  protection  against  the  former. 

1  Charbon  and  septicaemia.     Comptes  rendus  LXXXV. 

2  Comptes  rendus  LXXXVII.,  p.  47. 


280  BACTERIA  IN  INFECTIOUS   DISEASES. 

An  important  question,  which  has  received  the 
attention  of  several  investigators,  relates  to  the 
possibility  of  the  passage  of  the  bacillus  from 
the  circulation  of  a  pregnant  female,  through  the 
placenta,  to  the  foetus  in  utero.  It  is  well  known 
that  the  placenta  does  not  permit  of  the  pas- 
sage of  blood-corpuscles,  and  experimenters  very 
justly  reasoned  that  if  the  blood  of  the  foetus  of 
'  an  animal  which  has  succumbed  to  an  attack  of 
anthrax  is  free  from  bacilli  while  the  mother's 
blood  contains  them,  inoculation  experiments 
with  this  blood  should  furnish  strong  evidence  for 
or  against  the  germ  theory. 

The  observations  of  Brauell,  of  Davaine,  and 
of  Bollinger,  were  all  in  accord  as  to  the  absence 
of  the  bacilli  from  the  blood,  and  its  non-virulent 
character.  But,  more  recently,  Strauss  and  Cham- 
berland  have  shown  that  there  are  some  excep- 
tions to  this  rule,  and  that  occasionally  the  foetal 
blood  contains  a  few  bacilli.  This  was  proved  by 
culture  experiments,  and  when  the  bacilli  were 
present  the  blood  was  found  to  be  virulent,  when 
injected  in  sufficient  quantity. 

SYMPTOMATIC  ANTHRAX  ;  Clwrlon  tympiomaUque. 
—  This  disease,  according  to  Arloing,  Cornevin, 
and  Thomas,  is  characterized  by  the  presence 
of  a  microbe  which  has  distinct  morphological 
characters,  and  which  differs  essentially  from  the 
anthrax  bacillus.  It  is  shorter  and  broader  than 
B.  anil i  -  rounded  at  the  extremities,  is  ex- 


SYMPTOMATIC  ANTHRAX.  281 

tremely  mobile,  and  is  nearly  always  provided  at 
one  extremity  with  a  refractive  spore.  Sometimes 
the  rod  is  very  long  and  has  a  spore  at  each  ex- 
tremity. It  may  happen  that  the  microbe  is  only 
distinguished  by  this  spore,  as  the  rod  has  nearly 
the  same  refractive  index  as  the  fluid  in  which  it 
is  found.  The  writer  would  remark,  en  passant ', 
that  he  has  observed  bacilli  which  answer  very 
well  to  this  description,  in  putrid  blood,  and  es- 
pecially in  a  specimen  of  blood  sent  to  him  from 
Havana,  which  had  become  putrid  en  route.  This 
was  obtained  from  a  yellow-fever  patient,  post 
mortem.  Photo-micrographs  were  made  of  this 
organism,  and  heliotype  reproductions  of  these  are 
seen  in  Fig.  5,  Plate  II.,  and'  Fig.  4,  Plate  III. 
These  bacilli  are  endowed  with  active  motion, 
have  rounded  extremities,  and  very  commonly 
contain  a  highly  refractive  spore  at  one  end,  as 
seen  in  Fig.  2. 

According  to  the  authors  named,  symptomatic 
anthrax  occurs  especially  in  young  cattle,  of  six 
months  to  four  years,  and  in  lambs.  It  is  charac- 
terized by. loss  of  appetite,  debility,  and  lameness 
due  to  the  development  of  a  tumor.  Wherever 
situated,  this  tumor  is  irregular  in  form,  and  ex- 
tends in  every  direction  with  astonishing  rapidity. 
In  eight  to  ten  hours  it  attains  an  enormous  de- 
velopment. At  first  homogeneous  and  extremely 
painful,  the  tumor  becomes,  little  by  little,  insen- 
sible in  the  centre  and  crepitates  on  pressure. 
All  of  the  tissues  forming  this  tumor  are  black 


282  BACTERIA  IN  INFECTIOUS  DISEASES. 

and  friable.  When  incised,  bright  red  blood  es- 
capes, in  the  earlier  stage  of  development,  later 
a  liquid  resembling  venous  blood,  and  at  last  a 
frothy  serum.  The  tumor  may  be  deeply  buried 
in  the  muscles,  and  may  then  escape  observation. 
Death  usually  occurs  within  36  to  48  hours  after 
the  appearance  of  the  first  symptoms.  The  dis- 
ease is  always  fatal.  After  death  the  body  rap- 
idly becomes  inflated  by  an  accumulation  of  gas 
in  the  abdomen,  in  the  veins,  and  in  the  cellular 
tissue.  One  or  more  bloody  tumors  are  found 
among  the  muscles,  which,  when  incised,  present 
a  characteristic  black  color,  are  very  friable,  and 
infiltrated  with  gas.  The  digestive  organs  are 
usually  entirely  healthy,  and  the  liver  and  spleen 
are  normal  in  appearance  although  they  contain 
the  microbe  in  abundance. 

Symptomatic  anthrax  is  not  readily  communi- 
cated by  small  amounts  of  virus.  In  a  few  cases 
only  have  successful  inoculations  been  made  with 
the  pulp  of  diseased  glands  in  small  quantity. 
But  larger  amounts  of  the  infectious  material 
produce  the  characteristic  tumors.  In  suscepti- 
ble animals  a  few  drops  of  blood,  or  muscle  pulp, 
forced  into  the  cellular  tissue  produces  fatal  re- 
sults. Intra-venous  injections  of  as  much  as  2.6 
c.c.  of  the  pulp  from  a  tumor  are  tolerated  by  the 
calf,  sheep,  and  goat.  A  mild  sickness  results 
from  such  an  injection,  and  in  rare  cases  death 
occurs.  The  guinea-pig  is  susceptible,  but  the 
rabbit  is  not.  The  microbe  is  -said  to  present 


SYMPTOMATIC  ANTHRAX.  283 

different  characters  in  the  blood,  in  the  tumors 
among  the  muscles,  and  in  the  effused  serum  in 
the  connective  tissue. 

Immunity  is  said  to  result  from  intra-venous 
injection  of  material  containing  the  microbe. 
Subsequent  sub-cutaneous  injection  of  pulp  from 
a  tumor  produces  no  results  in  these  animals. 
The  value  of  this  method  has  been  tested  by  ex- 
periments upon  244  animals,  made  under  the 
authority  of  the  French  Government.  The  re- 
sults of  intra-venous  injection  differ  with  the 
amount  of  virus  employed.  When  the  quantity 
is  very  small,  general  disturbances  are  produced 
which  disappear  in  two  or  three  days,  leaving  the 
subject  immune.  When  the  dose  is  considerable, 
fatal  symptomatic  anthrax  is  produced.  The  ex- 
perimenters suppose  that  in  non-fatal  intra-venous 
injections  the  bacterium  multiplies  in  the  blood, 
but  is  prevented  by  the  endothelium  of  the  vessels 
from  entering  the  connective  tissue. 

Filtration  experiments  show  that  the  poison  is 
particulate,  and  the  authors  quoted  claim  to  have 
proved  that  the  bacterium  described  by  them  is 
the  veritable  cause  of  the  disease.  The  experi- 
ments recently  made  by  the  same  authors  to  de- 
termine the  comparative  value  of  disinfectants 
for  the  destruction  of  this  virus,,  seem  to  support 
their  deductions  as  to  the  essential  etiological  role 
of  the  microbe. 

The  preservation  of  virulence  after  exposure 
to  sulphurous  acid,  to  alcohol  saturated  with  cam- 


284  BACTERIA  IN  INFECTIOUS  DISEASES. 

phor,  etc.,  is  accounted  for  by  the  presence  of 
spores.  This  corresponds  with  Koch's  results  as 
to  the  resisting  power  of  the  spores  of  Bacillus 
anthrads,  which,  it  will  be  remembered,  are  not 
found  in  the  bacilli  as  they  occur  in  the  blood 
and  tissues  of  a  living  animal.  The  superior 
resisting  power,  as  regards  retention  of  virulence, 
of  the  fluids  of  symptomatic  anthrax  to  an  ele- 
vated temperature  is  also,  no  doubt,  due  to  the 
presence  of  spores.  In  a  recent  series  of  experi- 
ments Arloing,  Cornevin,  and  Thomas  have  deter- 
mined the  thermal  death-point  of  these  spores. 
Fresh  virus  lost  all  pathogenic  power  when  heated 
for  two  hours  at  80°  C.,  or  by  subjection  to  a  boil- 
ing temperature  for  twenty  minutes.  An  attenu- 
ated virus  of  different  degrees  of  power  could  be 
produced  by  subjecting  the  material  to  a  temper- 
ature lower  than  that  which  destroyed  it  entirely. 
Thymol  and  oil  of  eucalyptus  were  capable  of 
attenuating  the  virus  in  forty-eight  hours,  without 
destroying  the  vitality  of  the  microbes. 

In  symptomatic  anthrax,  contrary  to  the  usual 
rule  in  anthrax,  the  foetal  blood  is  virulent,  and  con- 
tains the  bacteria  to  which  this  virulence  is  ascribed. 

CEREBRO-SPINAL  MENINGITIS. —  Leyden  reports 
the  finding  of  "oval  micrococci,  in  great  numbers, 
occurring  both  singly  and  in  chains,"  in  recent 
lymph  obtained  by  a  hypodermic  syringe  from 
beneath  the  pia  mater  of  the  spinal  cord  in  a 
sporadic  case  of  this  disease. 


CEREBRO-SPINAL  MENINGITIS.  285 

CHOLERA.  —  Epidemiologists  find  it  necessary 
to  assume  the  existence  of  a  living  germ  in  order 
to  explain  in  a  satisfactory  manner  the  origin  and 
epidemic  extension  of  this  disease.  Evidently  the 
materies  morU  is  capable  of  self-multiplication  ex- 
ternal to  the  human  body ;  and  this  multiplication 
is  conditioned  by  circumstances  of  the  same  kind 
as  those  which  influence  the  development  of  the 
lowest  organisms,  —  heat,  moisture,  and  the  pres- 
ence of  organic  material  to  serve  as  nutritive 
pabulum  for  the  hypothetical  germ. 

Various  attempts  have  been  made  to  find  the 
cholera  germ  in  infected  atmospheres  and  in  the 
discharges  of  cholera  patients,  but  thus  far  no 
satisfactory  results  have  been  attained. 

Since  the  above  was  written,  Koch  has  an- 
nounced the  discovery  of  a  bacillus  believed  by 
him  to  be  the  much-sought  cholera  "  germ."  This 
is  a  comma-shaped,  mobile,  micro-organism  which 
is  found  in  the  rice-water  discharges  of  cholera 
patients,  and  in  the  intestines  of  those  dead  of  the 
disease.  When  death  occurs  during  the  stage  of 
reaction  the  bacilli  are  not  found  in  the  contents 
of  the  bowel,  but  within  the  mucous  membrane 
and  in  the  tubular  glands.  Extended  researches 
made  in  Egypt,  and  more  recently  in  France, 
have  shown  the  uniform  presence  of  this  bacillus 
in  cases  of  true  Asiatic  cholera,  and  its  absence 
from  the  discharges  of  patients  suffering  from  sim- 
ple diarrhoea,  dysentery,  and  other  intestinal  dis- 
orders. The  bacillus  forms  characteristic  colonies 


286  BACTERIA  IN  INFECTIOUS  DISEASES. 

in  gelatine  cultures  and  causes  liquefaction  of  the 
culture  medium.  Efforts  to  inoculate  the  lower 
animals  have  not  been  successful.  Nor  are  they 
likely  to  be;  for  several  experimenters  (Magen- 
die,  Meyer,  Lindsay)  had  previously  demonstrated 
the  insusceptibility  of  various  animals,  by  intro- 
ducing material  from  the  stools  of  cholera  patients 
into  the  stomach,  veins,  and  sub-cutaneous  tissue, 
with  a  negative  result. 

ERYSIPELAS.  —  The  infectious  nature  of  erysip- 
elas has  been  abundantly  demonstrated,  both  by 
clinical  and  experimental  evidence.  The  trans- 
mission of  vaccinal  erysipelas  from  one  child  to 
several  others,  and  the  communication  of  the  dis- 
ease by  instruments  previously  used  in  dressing 
erysipelatous  wounds,  has  been  noted  by  physi- 
cians. Orth  has  also  shown,  by  a  series  of  twenty- 
three  experiments,  that  the  disease  may  be  com- 
municated by  inoculation  from  man  to  the  lower 
animals. 

Numerous  observers — Hiiter,  Nepveu,  Wilde, 
Orth,  Wahlberg,  and  others — have  noted  the 
presence  of  micrococci  in  the  inflamed  tissues,  and 
especially  in  the  oedema  of  erysipelas. 

Fehleisen  has  recently  given  strong  experi- 
mental evidence  in  favor  of  the  pathogenic  role 
of  these  micrococci.  Not  only  has  he  demon- 
strated their  presence  in  every  case  of  erysipelas 
examined  by  him  (13  cases),  but  he  has  succeeded 
in  cultivating  them,  and  has  successfully  inocu- 
lated men  and  animals  with  the  cultivated  micro- 


ERYSIPELAS.  287 

organisms.  The  micrococci  were  very  numerous 
in  bits  of  skin  excised  from  the  diseased  surface 
in  cases  of  erysipelas,  and  were  commonly  ar- 
ranged in  chains.  They  were  never  found  in  the 
blood-vessels,  and  were  most  numerous  in  recently 
affected  parts ;  here  they  invaded  the  superficial 
layer  of  the  corium  and  the  sub-cutaneous  adipose 
tissue,  filling  the  lymphatics  and  the  lymph- 
spaces.  Fehleisen  succeeded  in  cultivating  these 
micrococci  by  placing  bits  of  excised  skin  upon 
the  surface  of  a  jellified  solution  of  gelatine. 
Here  they  produced  by  their  abundant  multipli- 
cation a  whitish  film,  which  was  easily  detached, 
and  was  composed  entirely  of  the  organisms. 
Nine  rabbits  were  inoculated,  and  in  eight  a 
characteristic  erysipelatous  rash  was  developed 
after  36  to  48  hours.  This  was  attended  with 
febrile  disturbance  at  the  outset.  In  a  few  days 
the  disease  ran  its  course  and  the  animals,  without 
exception,  recovered.  The  inoculations  were  upon 
the  ear,  both  with  micrococci  taken  directly  from 
a  patient,  and  with  cultivated  organisms.  The 
disease  extended  from  the  point  of  inoculation  to 
the  root  of  the  ear,  and  thence  to  the  head  and 
neck. 

In  one  case  the  ear  was  amputated  during  the 
height  of  the  disease,  and  the  presence  of  micro- 
cocci  demonstrated  in  the  lymphatics  of  the  af- 
fected part. 

Fehleisen  also  inoculated  the  pure,  and  culti- 
vated, organisms  upon  man,  with  a  successful 


288  BACTERIA  IN  INFECTIOUS  DISEASES. 

result  in  six  out  of  seven  cases.  The  period  of 
incubation  was  from  fifteen  to  sixty  hours,  after 
which  rigors,  followed  by  fever,  occurred ;  and  the 
typical  erysipelatous  rash  developed  itself,  and 
ran  the  usual  course. 

CHOLERA  OF  FOWLS,  cholera  des  poules.  —  Pas- 
teur has  furnished  satisfactory  experimental  evi- 
dence that  this  infectious  disease  of  the  domestic 
fowl  is  due  to  a  micrococcus,  which  he  has  culti- 
vated for  successive  generations  in  bouillon  made 
from  the  flesh  of  a  chicken ;  but  which  does  not 
multiply  in  yeast-water,  a  culture-medium  well 
suited  for  the  development  of  many  species  of 
bacteria. 

Inoculation  of  healthy  fowls  with  a  pure  culture 
of  this  micrococcus  gives  rise  to  the  disease ;  but 
not  invariably,  as  a  marked  difference  in  suscepti- 
bility exists  in  different  individuals.  Out  of  eighty 
fowls  inoculated  by  Salmon,  six  recovered,  twenty- 
five  were  not  visibly  affected,  and  forty-nine  died. 

One  attack  protects  from  subsequent  attacks, 
and  protective  inoculations  may  be  practised  with 
"attenuated  virus " prepared  by  Pasteur's  method, 
—  long  exposure  to  oxygen. 

The  most  potent  virus  is  that  obtained  from  a 
fowl  which  dies  from  a  chronic  form  of  the  disease. 
In  these  cases,  "the  fowl,  after  having  been  very 
sick,  grows  thinner  and  thinner,  and  resists  death 
for  several  weeks  or  months.  When  it  perishes, 
which  occurs  shortly  after  the  parasite,  located 


CHOLERA  OF  FOWLS.  289 

previously  in  certain  organs,  has  passed  into  the 
blood  and  increases  there,  we  observe  that  what- 
ever, may  have  been  the  original  virulence  of  the 
virus  at  the  time  of  inoculation,  that  taken  from 
the  blood  of  the  dead  fowl  has  a  considerable  viru- 
lence and  kills  ordinarily  ten  times  out  of  ten, 
twenty  out  of  twenty."  When  an  interval  of 
three  to  eight  months  is  allowed  to  elapse  between 
successive  cultures,  the  virulence  is  modified  more 
or  less  according  to  the  length  of  time.  But  each 
degree  of  attenuation  may  be  preserved  through 
a  series  of  cultivations  made  at  short  intervals 
(Pasteur).  It  is  necessary  to  cultivate  the  micro- 
coccus  in  contact  with  the  air  as  it  is  aerobic.  In 
Salmon's  experiments  it  was  observed  to  form  a 
mycoderma  upon  the  surface  of  the  culture-fluid. 
The  last-named  observer  states  that  the  micro- 
cocci  are  not  abundant  in  the  blood  of  a  fowl, 
drawn  from  a  vein  during  life,  but  that  they  are 
more  abundant  in  blood  taken  from  the  body  after 
death.  Putrefaction  destroys  the  potency  of  viru- 
lent fluids.  The  thermal  death-point  of  the  micro- 
coccus  has  been  fixed  by  Salmon  as  somewhere 
between  124°  and  140°  Fahr.  Of  three  fowls  in- 
oculated with  virulent  blood  heated  to  124°  for 
fifteen  minutes,  two  died ;  while  two  fowls  inocu- 
lated with  blood  that  had  been  heated  to  140°  for 
the  same  time,  remained  in  good  health ;  one  was 
subsequently  proved  to  be  susceptible  by  inocula- 

1  Comptes  rendus  XCL,  p.  375. 
19 


290  BACTERIA  IN  INFECTIOUS  DISEASES. 

tion  with  active  virus,  but  the  other  resisted  such 
inoculation. 

This  corresponds  very  closely  with  the  thermal 
death-point  of  the  micrococcus  of  septicaemia  in 
the  rabbit,  and  the  micrococcus  of  pus,  as  deter- 
mined by  the  writer,  and  is  strong  evidence  in 
support  of  the  view  that  the  virulence  of  the  fluid 
containing  it  depends  upon  the  vitality  of  the 
micro-organism.  The  resistance  to  various  chemi- 
cal reagents,  as  determined  by  Salmon,  also  cor- 
responds very  closely  with  results  obtained  by  the 
writer  in  similar  experiments  with  the  micrococ- 
cus of  induced  septicaemia  in  the  rabbit.  These 
two  species  of  Micrococcus,  however,  have  distinct 
physiological  properties,  as  the  writer  has  proved 
the  innocuousness  of  the  oval  micrococcus  of  septi- 
caemia in  the  rabbit  when  injected  into  the  muscles 
of  fowls.  Pasteur  finds  no  difference,  morphologi- 
cally, between  the  organism  which  produces  the 
"new  disease"  described  by  him  (see  p.  365),  and 
that  which  produces  choUra  des  poules.  He  also 
found  that  this  micrococcus  of  induced  septicaemia 
in  the  rabbit  does  not  produce  the  slightest  ill- 
effect  when  injected  into  fowls.  Toussaint  has 
claimed  that  fowl-cholera  and  acute  septicaemia  in 
animals,  produced  by  the  injection  of  the  blood  of 
animals  dead  with  cholera,  or  of  animal  matters 
more  or  less  putrid,  are  identical  diseases  and  due 
to  the  same  parasite.  He  says :  "  Since  the  ex- 
periments of  Coze  and  Feltz  in  1866,  of  Davaine, 
Vulpian,  Bouley,  etc.,  and  the  labors  of  the  Ger- 


DIPHTHERIA.  291 

man  savants,  it  is  demonstrated  that  certain  ani- 
mal matters  undergoing  putrefaction,  inoculated 
under  the  skin  of  the  rabbit  and  of  some  other 
animals,  produces,  after  several  inoculations,  a 
malady,  rapidly  fatal,  inoculable  with  extremely 
minute  quantities,  and  which  reproduces  itself  in- 
definitely. The  presence  of  a  parasite  in  septi- 
caemia which  presents  this  character,  has  been 
sustained,  then  denied.  ...  I  can  truly  say,  after 
several  series  of  experiments  comprising  more  than 
two  hundred  and  fifty  cases,  that  in  the  malady  of 
rapid  form  which  kills  the  rabbit  in  ten  to  twenty 
hours,  and  which  is  inoculated  so  easily  into  birds, 
there  exists  a  microbe  of  well-determined  form  and 
properties,  of  which  the  action  is  always  identi- 
cal, which  is  that  which  Pasteur  has  so  perfectly 
studied,  and  of  which  I  have  already  demonstrated 
the  presence  in  chicken  cholera,"  l 

DIPHTHERIA.  —  The  presence  of  micro-organisms, 
and  especially  of  micrococci  in  diphtheritic  exuda- 
tions, has  been  observed  by  numerous  investiga- 
tors, and  was  a  priori  to  have  been  expected, 
inasmuch  as  the  healthy  human  mouth  is  con- 
stantly infested  with  micrococci  and  other  forms 
of  bacteria.  Oertel  says :  u  They  were  discovered 
as  far  back  as  1868,  by  Buhl,  Hueter,  and  myself, 
in  false  membranes,  the  blood,  and  the  tissues ;  in 
like  manner  they  were  demonstrated  by  Von  Rech- 
linghausen,  Wassiloff,  Waldeyer,  Klebs,  Eberth, 
Heiberg,  and  others,  in  the  most  different  organs 

1  Comptes  rendus  XCL,  p.  302. 


292  BACTERIA  IN  INFECTIOUS  DISEASES. 

and  tissues/' 1  The  author  quoted  is  very  positive 
as  to  the  etiological  role  of  these  micrococci,  and 
agrees  with  Eberth  in  the  statement,  "Without 
micrococci  there  can  be  no  diphtheria."  The  Micrococ- 
cus  diphtheria,  Oertel,  is  described  as  follows,  in  a 
later  work  : 2  "It  has  an  oval  form,  with  a  length 
of  1-1. 5  n,  and  a  breadth  of  0.3  /* ;  larger  indi- 
viduals, found  nearer  the  surface,  being  4.2  /*  long, 
and  1.1  /x  broad.  Where  the  individuals  are  more 
scattered,  they  occur  mostly  in  pairs,  rarely  a 
number  connected  into  a  torula-like  chain.  When 
present  in  masses,  the  cells  lie  so  close  together 
that  it  is  difficult  to  determine  whether  they  are 
connected  or  not.  They  are  then  imbedded  in  a 
gelatinous  envelope,  and  thus  combined  in  masses 
into  a  colony."  3 

The  inoculability  of  the  disease  has  been  proved 
by  experiments  upon  animals ;  and  filtration 
experiments  (Eberth)  show  that  the  infectious 
element  in  diphtheritic  exudation  is  participate. 
Klebs,  who  has  the  credit  of  first  resorting  to  the 
method  of  "  fractional  cultivations,"  claims  to  have 
produced  diphtheria  in  animals  by  inoculating  them 
with  pure-cultures  of  the  micrococcus,  and  to  have 
subsequently  recognized  the  parasite  in  their  blood 
and  tissues. 

According  to  Ewart  and  Simpson,  the  patho- 
genic organism  of  diphtheria  is  a  minute  spore 

1  Cyclopaedia  of  the  Practice  of  Medicine,  Ziemssen,  Vol.  I.  p.  690. 

2  Zur  Aetiologie  der  Infectionskrankhciten,  1881. 

8  Quoted  from  Journal  Roy.  Mic.  Soc.  Ser.  II.,  Vol.  IL  p.  88. 


DIPHTHERIA. 


293 


Fig.  10. 
Copied  from  a  photo-micrograph ;  amplification  1000  diameters 

which  develops  into  long  slender  bacilli  upon  the 
surface  of  the  tonsils,  etc.,  when  for  any  reason 
they  are  denuded  of  their  superficial  epithelium. 
The  writer,  while  pursuing  certain  experimental 
investigations  in  Baltimore  (1881)  received,  from 
Dr.  H.  C.  Wood,  material  from  the  fauces  of 
patients  suffering  from  diphtheria,  and  also  from 
scarlet  fever  patients,  and  made  photo-micrographs 
of  the  micro-organisms  found  in  the  various  speci- 
mens. 

In  the  specimens  marked  "  scarlet  fever  mate- 
rial," slender  filaments,  containing  endogenous 
spores,  were  found,  which  correspond  with  those 
described  by  the  writers  named  as  peculiar  to  diph- 
theria. (See  Fig.  10.) 

Letzerich  differs  from  other  German  observers 


294  BACTERIA  IN  INFECTIOUS  DISEASES. 

in  regarding  a  true  fungus,  of  the  hyphomycetous 
family,  as  the  specific  contagion  of  diphtheria.1 

In  the  same  "  scarlet  fever  material,"  above 
referred  to,  the  mycelium  of  a  hyphomycetous 
fungus  was  found  (Fig.  10),  and  also  groups  of 
spherical  bodies  which  seemed  to  be  the  spores  of 
a  fungus  of  this  nature  (Fig.  11). 

Numerous  micrococci  were 
found  in  the  specimens 
marked  "  diphtheritic  mate- 
rial, Ludington,"  which  did 
not  differ  morphologically 
from  those  which  the  writer 
had  previously  cultivated  and 
photographed  from  normal 
Flg  n-  human  saliva.  (See  Fig.  1, 

Copied  from  a  photo-micrograph  ;      Plofo     VT  ^ 
amplification  1000  diameters. 

It   is  apparent   from  what 

has  been  said  that  the  micrococci,  bacilli  (Ewart), 
and  fungi  (Letzerich),  which  have  been  supposed 
to  be  the  cause  of  diphtheria,  present  no  mor- 
phological characters  by  which  they  can  be  dis- 
tinguished from  similar  organisms  which  are 
found  in  the  mouth  and  fauces  of  patients  suf- 
fering from  another  disease  in  which  the  throat 
is  involved  —  scarlet  fever,  and  of  healthy  indi- 
viduals—  at  least  so  far  as  the  micrococci  are 
concerned. 

Morphological    identity    cannot,    however,    be 
taken   as    proof    of    physiological    identity,    and 

1  Kinnicutt  in  Supplement  to  Ziemssen's  Cyclopaedia,  p.  82. 


DIPHTHERIA.  295 

indeed  we  have  ample  evidence  that  certain  or- 
ganisms demonstrated  to  have  pathogenic  proper- 
ties do  not  differ  in  form  from  others  known  to  be 
harmless. 

The  elaborate  and  carefully  conducted  inves- 
tigations of  Wood  and  Formad,  made  under  the 
auspices  of  the  National  Board  of  Health,  give 
support  to  the  view  that  the  micrococcus  found  by 
them  in  diphtheritic  exudations  is  the  infectious 
agent  in  this  disease. 

In  an  editorial  in  the  "Medical  Times"  (April 
22,  1882),  Dr.  Wood  says  :- 

"  A  number  of  experiments  were  made  upon  the 
effect  of  boiling  the  membrane,  and  it  was  found  that  if 
the  heat  were  maintained  for  only  four  or  five  minutes 
the  contagious  power  was  not  always  destroyed,  but 
that  when  the  boiling  was  continued  for  fifteen  minutes 
or  longer,  inoculation  with  the  virus  always  failed  to 
produce  any  local  or  general  effects.  Culture  experi- 
ments with  this  innocuous  virus  showed  that  the  boil- 
ing had  killed  the  micrococci,  which  entirely  refused  to 
grow.  It  is  scarcely  necessary  to  point  out  the  con- 
firmation this  lends  to  the  belief  that  the  micrococci  are 
the  materies  morbi.  .  .  . 

"A  number  of  cultures  were  also  made,  and  inocula- 
tions with  the  liquid  practised.  In  six  or  eight  in- 
stances the  second,  third,  or  fifth  generation  of  cultured 
plants  caused  the  death  of  the  rabbit.  In  all  these 
cases  micrococci  were  abundant  in  the  blood  and  inter- 
nal organs.  In  some  animals  the  local  exudations  were 
marked,  and  resembled  those  of  diphtheria  ;  but  in  other 
rabbits  the  local  symptoms  were  only  slight  swelling 
and  infiltration  of  the  surrounding  tissues  with  serous 


296  BACTERIA  IN  INFECTIOUS  DISEASES. 

liquid  containing  an  abundance  of  micrococci."  [It 
must  be  remembered  that  the  injection  of  normal  human 
saliva  into  rabbits  produces  similar  results.] 

Wood  and  Formad  give  the  following  summary 
statement  of  the  conclusions  reached  by  them  as 
a  result  of  their  experimental  investigation,  in 
their  final  report,  which  has  only  recently  been 
published,  although  it  was  sent  to  the  National 
Board  of  Health  in  September,  1882  :  — 

"  Micrococci  are  an  essential  part  of  the  diphtheritic 
process,  being  always  found  locally  at  the  seat  of 
inflammation,  and,  when  blood-poisoning  develops,  also 
in  the  blood,  attacking  and  destroying  the  white  blood- 
corpuscles,  forming  emboli  in  the  kidneys,  spleen,  and 
other  organs.  .  .  .  The  micrococci  of  diphtheria  do  not 
differ,  so  far  as  observed,  from  the  micrococci  of  furred 
tongue,  etc.,  except  in  their  tendency  to  grow  in  culture- 
fluids.  .  .  .  The  theory  of  the  disease,  which  we  would 
deduce  from  these  facts,  is  that  the  micrococcus  which 
causes  the  diphtheria  is  not  a  specific  organism  different 
from  that  common  to  healthy  and  inflamed  throats,  but 
is  an  active  state  of  that  organism  ;  that  certain  cir- 
cumstances outside%  of  the  human  body  are  capable  of 
throwing  this  common  micrococcus  into  the  condition 

NOTE. —  We  remark  that  the  fact  mentioned  on  page  205,  with  refer- 
ence to  the  failure  of  four  or  five  minutes'  boiling  to  destroy  the  conta- 
gious power  of  diphtheritic  membrane,  in  some  instances,  is  opposed  to 
the  view  that  the  micrococcus  found  in  it  is  the  contagious  principle ; 
for  the  thermal  death-point  of  this  micrococcus  is  only  140°  Fnlir.,  as 
determined  by  the  writer's  experiments  (see  page  223).  It  may  In •,  how- 
ever, that  the  masses  used  in  the  experiments  in  which  the  contagious 
power  was  not  destroyed  were  not  penetrated  by  the  heat,  during  this 
short  exposure,  and  that  micrococci  in  the  interior  of  the  mate-rial 
escaped  destruction  for  this  reason. 


DISEASE  PRODUCED  BY  BACILLI  297 

of    active    growth,   and    engendering   an   epidemic   of 
diphtheria." 

Several  observers  have  noted  the  occurrence  of 
an  infectious  disease  among  fowls,  attended  with 
the  formation  of  false  membrane  in  the  trachea, 
which  is  supposed  by  some  to  be  identical  with 
diphtheria  in  man. 

Nicati  has  successfully  inoculated  various  ani- 
mals with  the  false  membrane,  and  states  that  the 
outbreak  among  fowls  studied  by  him  coincided 
with  an  increase  of  diphtheria  among  the  inhabi- 
tants in  the  vicinity. 

DISEASE  PRODUCED  BY  BACILLI.  —  Abstract  of 
a  paper  by  J.  Cossar  Ewart,  M.  D.,  Professor  of 
Natural  History,  University  of  Edinburgh :  — 

"  About  the  end  of  March  of  this  year,  a  new  form 
of  fever  made  its  appearance  in  Aberdeen.  The  fever 
began  with  the  usual  symptoms  ;  there  was  well-marked 
rigor  ;  then  a  sense  of  coldness  for  some  hours,  accom- 
panied with  great  depression ;  the  pulse  was  rapid,  and 
the  temperature  increased  in  some  cases  to  105°  Fahr. 
In  the  worst  cases  there  was  delirium.  One  of  the  most 
characteristic  symptoms  was  an  affection  of  the  deep 
cervical  glands  near  the  angle  of  the  jaw ;  the  glands 
enlarged ;  there  was  a  feeling  of  fulness  about  the 
throat,  congestion  of  the  tonsils,  and  pain  along  the 
course  of  the  lymphatics  of  the  side  of  the  neck  affected. 
In  from  twenty-four  to  forty-eight  hours  the  fever  sub- 
sided, leaving  the  patient  in  a  state  of  great  exhaustion. 
In  most  cases  there  was  a  relapse,  which  corresponded 
exactly  with  the  first  attack,  with  the  difference  that 
another  set  of  glands  and  lymphatics  was  affected. 


298  BACTERIA  IN   INFECTIOUS  DISEASES. 

"  After  this  relapse,  there  was  again  apparent  recov- 
ery, and  then  a  second  relapse  ;  in  some  cases  there 
were  as  many  as  six  relapses  occurring  regularly  eveiy 
second  day.  In  nearly  all  the  cases,  recovery  was  slow  ; 
and,  in  some,  abscesses  formed  near  the  angle  of  the 
jaw,  and  in  the  region  of  the  jaw.  In  three  cases 
the  disease  proved  fatal. 

44  When  an  inquiry  was  instituted,  it  was  found  that 
over  three  hundred  individuals  had  suffered  from  this 
disease,  and  that  all  the  sufferers  had  been  using  milk 
from  the  same  dairy.  A  sample  of  milk  secured  for 
examination,  when  the  epidemic  was  at  its  height,  was 
found  to  contain  numerous  micrococci,  spores  of  fungi, 
and  spores  which  resembled  those  of  Bacillus  anthracis, 
—  the  organism  which  is  associated  with  splenic  fever. 
When  cultivated,  the  spores  germinated,  first  into  ex- 
ceedingly delicate  bacilli,  and  then  into  spore-bearing 
filaments.  On  inoculating  rats  with  the  milk  contain- 
ing the  spores,  death  followed  in  from  eighteen  to 
twenty-four  hours.  The  tissues  of  the  rats,  especially 
in  the  region  of  the  neck,  were  infiltrated  with  bacilli, 
which,  on  cultivation,  developed  into  spore-bearing  fila- 
ments. Inoculation  proved  both  bacilli  and  spores  to 
be  as  virulent  as  the  original  spores  found  in  the  milk. 
Confirmatory  evidence  of  the  relation  of  the  bacillus  to 
the  disease  was  obtained  by  the  examination  of  pus  from 
an  abscess  over  the  angle  of  the  jaw  of  one  of  the  suffer- 
ers. This  pus  contained  spores  and  bacilli  similar  to 
those  found  in,  or  developed  from,  the  milk.  Rats  in- 
oculated with  a  minute  quantity  of  the  pus,  suffered 
and  died  in  the  same  way  as  the  rats  infected  with  the 
milk,  and  the  milk  cultivations.  Further  investigations 
proved  that  the  organisms  had  been  added  to  the  milk 
along  with  water.  .  .  . 

"Experiments,  after  the  methods  employed  by  Bur- 


GLANDERS.  299 

don-Sanderson,  Pasteur,  Greenfield,  and  Buchner, 
showed  (1)  that  this  bacillus  could  not  be  converted 
into  the  hay  bacillus  (B.  subtilis)  ;  (2)  that  the  cultiva- 
tions became  gradually  less  active  until  they  were  quite 
innocuous ;  (3)  that,  when  filaments  were  kept  for  a 
time  at  a  temperature  which  prevented  the  formation  of 
spores,  the  virulence  became  attenuated,  and  ultimately 
disappeared."  —  British  Med.  Journal,  Nov.  4th,  1882. 

FATAL  EPIDEMIC  AMONG  FISH  CAUSED  BY  BAC- 
TERIA.—  Dr.  Ogle  gives  an  account  of  an  epidemic 
among  the  perch  in  Lake  Geneva,  studied  by  Farel 
and  Du  Plessis.  The  fish  became  sluggish,  suffered 
from  a  bilious  diarrhoea,  and  the  anterior  part  of 
the  head  and  body  was  injected  with  blood.  The 
intestines  were  distended  with  a  transparent  fluid 
containing  myriads  of  bacteria.  The  blood  was 
diffluent,  and  contained  "  bacteria  and  vibrios " 
while  the  fish  was  still  living.  Experiments 
proved  that  the  disease  was  not  communicable  to 
batrachia  or  to  warm-blooded  animals. 

Professor  Huxley  has  given  an  interesting  ac- 
count of  an  infectious  disease  of  the  salmon,  which 
is  apparently  produced  by  a  Saprolegnia  identical 
with  that  which  infests  the  bodies  of  dead  insects. 

GLANDERS.  —  The  discovery  of  the  parasite  of 
glanders  has  recently  been  announced  by  Schutz 
and  Loeffler,  who  have  pursued  an  experimental 
investigation  relating  to  the  etiology  of  this  infec- 
tious disease  of  the  horse,  in  Koch's  laboratory  in 
Berlin.  The  parasite  is  said  to  be  a  bacillus  re- 
sembling that  of  tuberculosis.  It  is  found  in  the 


300  BACTERIA  IN  INFECTIOUS  DISEASES. 

tubercles  which  are  characteristic  of  the  disease. 
The  culture-medium  employed  was  sterilized  serum 
from  the  blood  of  the  horse  or  of  the  sheep.  This 
was  inoculated  with  a  bit  cut  from  one  of  the 
tumors,  due  precautions  being  taken  to  prevent 
accidental  contamination.  The  bacillus  multiplied 
abundantly  in  the  course  of  a  few  days.  Animals 
of  various  species  were  inoculated  with  pure-cul- 
tures, and  were  found  to  differ  as  to  susceptibility. 
As  a  rule,  ulcers  occurred  at  the  point  of  inocula- 
tion, in  rabbits,  guinea-pigs,  mice,  etc.,  which  had 
an  indurated  base,  and  the  lymphatic  glands  in 
the  vicinity  of  these  were  tumefied  and  indurated. 
When  the  dose  was  large,  inflammation  of  the  tes- 
ticles, ovaries,  and  other  organs,  was  liable  to  occur. 
Some  of  the  animals  died  in  the  course  of  a  few 
days.  In  these,  bacilli  were  found  which  could  be 
propagated  by  cultivation,  but  which  were  smaller 
than  those  found  in  the  original  material. 

Two  horses  were  inoculated  successfully,  and  one 
died  at  the  end  of  fourteen  days.  Both  exhibited 
characteristic  symptoms  of  the  disease. 

In  a  case  of  acquired  glanders  in  man,  recently 
studied  by  Wassilieff,  bacilli,  resembling  those  de- 
scribed by  the  authors  quoted,  were  found  in  the 
nasal  secretion,  in  blood,  and  in  pus  from  pustules. 
They  were  especially  abundant  in  the  unripe  pus- 
tules, and  nearly  all  contained  four  to  six  spores. 

Evidence  of  the  inoculability  of  glanders  from 
the  horse  to  the  rabbit,  and  from  the  rabbit  to  the 
ass,  has  also  been  presented  by  Galtier,  in  a  com- 
munication to  the  French  Academy  of  Sciences. 


GONORRHOEA.  301 

This  author  states,  however,  that  it  is  not  trans- 
mitted with  certainty,  so  that  the  rabbit  cannot  be 
used  as  a  test  in  doubtful  cases,  inasmuch  as  posi- 
tive results  alone  are  of  value.  In  successful  cases 
the  lesions  resemble  those  of  purulent  infection, 
and  caseous  deposits  form  at  the  point  of  inocula- 
tion. It  is  only  exceptionally  that  lesions  are 
found  in  the  lungs  and  nasal  mucous  membrane. 

GONORRHOEA.  —  The  constant  presence  of  micro- 
cocci  in  the  pus  of  specific  urethretis  has  now  been 
verified  by  numerous  observers.  Neisser  of  Bres- 
lau  is  said  to  have  first  observed  them,  and  in  a 
paper  published  in  1879  he  advances  evidence  in 
favor  of  the  belief  that  they  are  the  cause  of  the 
specific  virulence  of  the  fluid  in  which  they  are 
found.  According  to  this  author  and  to  Weiss 
(1880),  these  micrococci  are  found  in  gonorrhoeal 
pus  from  the  male  urethra,  and  in  that  from  the 
female  vagina,  in  blenorrhcea  neanotorum,  and  in 
gonorrhoeal  ophthalmia.  On  the  other  hand,  Neisser 
failed  to  find  them  in  pus  from  other  sources  — 
chancres,  bubo,  etc.  Weiss  also  confirms  Neisser 
in  this,  and  states  that  they  are  not  present  in  the 
secretions  of  simple  urethretis.  Eecently  this 
subject  has  been  investigated  in  a  painstaking 
manner  by  Mr.  A.  S.  Keyser  (medical  student  in 
the  University  of  Maryland).  His  observations 
fully  confirm  Neisser  as  to  the  constant  presence 
of  the  "  gonococcus "  in  specific  purulent  dis- 
charges, and  its  absence  from  non-specific  pus 
from  various  sources. 


302  BACTERIA  IN  INFECTIOUS  DISEASES. 

Neisser  claims  that  this  micrococcus  has  distinct 
morphological  characters,  and  describes  it  as  fol- 
lows :  The  micrococcus,  at  first  round,  becomes 
oval,  and  then  divides  transversely,  forming  a 
pair.  The  individual  members  of  this  pair  are 
soon  separated  from  each  other  by  a  slight  inter- 
val, and  each  becomes  oval  and  divides  at  right 
angles  to  the  first  line  of  division,  thus  forming  a 
group  of  four.  These  groups  are  seen  in  the  in- 
terior of  the  pus  cells,  and  in  some  cases  they  are 
so  numerous  that  the  cells  are  completely  filled 
with  them,  and  resemble  very  closely  the  plasma 
cells  which  have  been  described  by  Ehrlich  (see 
Figs.  12  and  13). 

The  writer  is  able  to  confirm  Neisser,  as  to 
the  presence  of  these  micrococci  in  gonorrhoea! 
pus,  and  as  regards  the  correctness  of  his  descrip- 
tion of  their  morphological  characters  and  mode 
of  grouping  —  in  pairs  of  oval  elements  and  in 
fours  as  a  result  of  transverse  division  in  two 
directions.  But  his  observations  have  not  led  him 
to  the  conclusion  that  these  morphological  char- 
acters are  peculiar  to  the  micrococcus  of  gonor- 
rhoeal  pus  (consult  bibliography  for  titles  of  his 
papers  upon  this  subject).  Thus  in  Fig.  G,  Plate 
VI.,  we  have  a  photographic  representation  of  a 
micrococcus  of  the  same  dimensions,  and  which 
multiplies  in  the  same  manner,  which  I  have  fre- 
quently found  in  normal  human  saliva,  commonly 
attached  to  the  surface  of  (or  imbedded  in  the 
interior  of?)  an  epithelial  cell,  where  it  forms 


GONORRHCEA.  303 

little  groups,  as  seen  in  the  figure,  exactly  re- 
sembling those  found  in  the  cells  of  gonorrhceal 
pus.  The  photo-micrograph  was  made  from  a 
specimen  obtained  by  cultivating  the  organisms 
found  in  normal  saliva  in  an  acid  solution  of  malt 
extract.  In  my  paper  published  in  Vol.  II,  No.  2, 
of  i(>  Studies  from  the  Biological  Laboratory,  Johns 
Hopkins  University  "  (Bacteria  in  Healthy  Indi- 
viduals), this  micrococcus  was  incorrectly  de- 
scribed as  a  species  of  Sarcim,  as  "  division  by  two 
perpendicular  partitions  in  such  a  manner  that 
multiplication  takes  place  in  two  directions  "  is 
given  as  a  distinctive  character  of  this  genus  (see 
p.  96  of  the  present  volume). 

It  is  well  known,  from  the  observations  of 
numerous  microscopists,  that  pus  from  various 
sources  —  e.  g.,  acute  abscesses,  surgical  injuries, 
etc.  —  contains  micrococci. 

Ogsten  has  given  much  attention  to  the  study 
of  these,  and  in  his  report  on  "  Micro-organisms  in 
Surgical  Diseases,"  he  gives  figures  of  micrococci 
which  resemble  very  closely,  if  they  are  not  iden- 
tical with,  the  "gonococri"  of  Neisser.  In  his  de- 
scription of  these  he  says  :  — 

"In  the  chain-form,  division  occurred  in  only  one 
direction,  through  a  plane  midway  between  two  given 
poles,  so  that  a  pair  of  cocci  growing  formed  a  chain 
of  four ;  this  grew  into  a  chain  of  eight.  ...  In  the 
grouped  form,  fission  took  place  in  any  direction,  a  sin- 
gle coccus  seemingly  dividing  into  two,  three,  or  four 
cocci,  and  a  continuance  of  this  forming  the  groups. 
Many  of  the  masses  had  evidently  been  produced  by 


304 


BACTERIA  IN  INFECTIOUS  DISEASES. 


Fig.  12. 
Pus  cell  invaded  by  micrococci,  Ogsten.     X  2600  diameters. 

pairs  being  first  formed,  each  of  which  again  formed 
pairs,  and  so  on.  ...  In  some  cases,  unusually  large 
oval  cocci  existed,  chiefly  in  pairs.  .  .  .  Sufficient  evi- 
dence was  not  obtained  to  decide  whether  these  differ- 
ent appearances  indicated  different  species  of  micrococci ; 
but  the  constancy  with  which  chains  produced  only 
chains,  and  groups  only  groups,  in  the  experiments  that 
fall  to  be  detailed  subsequently,  rather  favored  the 
suspicion  of  their  being  so." 

The  invasion  of  a  pus  cell  by  micrococci  is 
shown  in  Fig.  12,  which  is  copied  from  the  plate 
accompanying  Ogsten's  report.  When  due  allow- 


GONORRHOEA. 


305 


Fig.  13. 

From  gonorrhoea!  pas.     Copied  from  a  photo-micro- 
graph.   X  1000  diameters. 


ance  is  made  for 
the  difference  in 
amplification,  it 
must  be  admitted 
that  the  resem- 
blance is  very 
striking  to  the  pus 
cell,  from  gonor- 
rhoeal  pus,  filled 
with  micrococci, 
which  is  seen  in 
the  centre  of  Fig. 
13,  which  is  copied 
from  a  photo-mi- 
crograph made  by  the  writer. 

In  a  recent  series  of  experiments  relating  to  the 
comparative  value  of  disinfectants,  the  writer  had 
under  daily  observation,  for  several  weeks,  pure 
cultures  of  the  micrococcus  of  gonorrhceal  pus,  and 
of  the  micrococcus  from  pus  contained  in  an  acute 
abscess  (whitlow).  Many  successive  generations 
of  these  micro-organisms  were  cultivated  in  the 
little  hermetically-sealed  flasks  described  on  p.  176. 
Culture  No.  1,  in  one  series,  was  obtained  by  inoc- 
ulating the  sterilized  bouillon  in  such  a  flask  with  a 
minute  drop  of  gonorrhoeal  pus  at  the  moment  of 
its  escape  from  the  meatus  iinnarius.  In  the  other 
series,  a  minute  drop  of  pus  from  a  deep-seated 
abscess  was  used  in  like  manner  to  inoculate  cul- 
ture No.  1  at  the  moment  of  its  escape  from  a 

deep  incision.     No  difference  was  detected  in  the 

20 


306  BACTERIA  IN  INFECTIOUS  DISEASES. 

morphological  characters,  or  in  the  behavior  in  a 
culture-fluid,  between  the  micrococci  from  these 
two  sources.  In  both  cases  multiplication  oc- 
curred sometimes  in  one  direction,  forming  a 
linear  series,  —  torula-form,  —  and  sometimes  in 
two  directions,  forming  groups  of  four.  Some- 
times a  group  of  three  would  be  seen,  in  which 
one  large  oval  micrococcus  was  faced  by  two 
smaller  ones,  which  evidently  had  resulted  from 
the  transverse  division  of  one  member  of  a  pair 
of  oval  elements. 

My  observations  show  that  the  microscopic 
plants  under  consideration  vary  considerably  as  to 
size  in  the  same  culture-fluid ;  and  indifferent  media 
they  present  marked  differences  hi  this  respect. 
The  individual  cocci  in  a  group,  like  that  in  Fig.  5, 
Plate  VI.  may  be  seen,  by  close  inspection,  to 
vary  considerably  in  size.  The  grouping,  also, 
depends,  to  some  extent,  at  least,  upon  whether 
they  are  favorably  situated  for  vigorous  growth, 
or  otherwise.  When  in  a  limited  quantity  of 
culture-fluid  the  pabulum  required  for  their  de- 
velopment is  exhausted,  they  settle  to  the  bot- 
tom, where  they  are  found  in  little  masses,  or 
as  a  pulverulent  precipitate ;  and  the  associa- 
tion into  chains  or  groups  of  four  is  no  longer 
observed. 

The  claim,  then,  made  by  Neisser,  "  that  there 
is  present  in  the  purulent  discharge  of  gonorrhoea, 
whether  from  urethra,  vagina,  or  conjunctiva,  a 
micrococcus  not  found  in  other  pus,  distinguished 


GONORRHCEA.  307 

by  its  size,  shape,  and   mode  of  reproduction"1 
does  not  seem  to  the  writer  to  be  sustained. 

My  own  observations,  however,  agree  with  those 
of  Neisser  as  to  the  constant  presence  of  oval 
micrococci,  mostly  arranged  in  groups  of  two  and 
four,  in  the  pus  of  gonorrhoea  —  invading  the  pus 
cells  —  and  I  have  failed  to  observe  this  arrange- 
ment in  pus  from  other  sources,  although  I  have 
seen  it  in  micrococci  infesting  the  shed  epithelium 
present  in  normal  saliva.  The  observations  of  Dr. 
Ogsten  have,  however,  been  far  more  extended 
than  my  own,  and  he  records  the  fact  that,  in  a 
certain  proportion  of  the  specimens  of  pus,  from 
acute  abscesses  and  other  sources,  which  he  ex- 
amined, this  mode  of  grouping  was  seen,  although 
the  chain-form  was  more  common.  He  says :  — , 

"In  some  cases,  unusually  large  cocci  existed,  chiefly 
in  pairs.  For  the  most  part  these  varieties  existed  in 
separate  abscesses,  but  it  frequently  occurred  that  an 
abscess  contained  both  chains  and  groups.  Out  of  sixty- 
four  abscesses  where  this  point  was  specially  noted, 
seventeen  contained  chains  only,  thirty-one  groups  only, 
and  sixteen  both  forms,  or  only  pairs." 

In  this,  as  in  other  infectious  diseases,  the  only 
satisfactory  evidence  that  the  micro-organisms 
present  in  the  virulent  material  are  the  infec- 
tious agents,  is  to  be  derived  from  inoculation 
experiments  with  a  pure-culture.  Unfortunately 
for  science,  but  not  for  the  animals,  the  lower 

1  Belfield,  in  his  Cartwright  Lectures.      The  Medical  Record,  Vol. 
XXIII.  No.  10,  p.  253. 


308  BACTERIA  IN  INFECTIOUS  DISEASES. 

animals  commonly  used  in  experimental  studies 
of  this  nature  are  not  susceptible  to  inoculations 
in  the  urethra,  the  vagina,  or  the  conjunct! val 
sac,  with  the  most  virulent  gonorrhceal  pus.  This 
fact  is  established  by  the  experiments  of  several 
independent  observers,  and  has  been  verified  by 
the  writer  as  regards  the  dog,  the  rabbit,  and  the 
guinea-pig. 

"  Ktfnigstein  has  made  frequent  inoculation  experi- 
ments with  the  secretions  of  blenorrhoea  neonatorum. 
This  was  smeared  into  the  eyes  of  dogs  and  rabbits; 
and  in  some  cases  after  so  doing  the  eye  was  sewn  up. 
Here  all  results  were  negative,  even  those  made  on 
puppies  which  were  still  sucking.  In  speaking  of  the 
microscopic  examination  of  the  secretions,  Konigstein 
confirms  Neisser's  discovery,  but  does  not  agree  with  him 
in  considering  the  diplococci  as  characteristic  of  a  gonor- 
rhosal  inflammation  of  a  mucous  membrane"  (Quoted 
from  Keyser,  italics  by  writer.) 

Eklund  also  finds  that  the  "gonococci"  of  Neisser 
are  uniformly  present,  but  he  decidedly  rejects  the 
opinion  that  they  constitute  in  an  exclusive  sense 
the  microbes  of  blennorrhagia,  since  he  has  dis- 
covered organisms  precisely  similar  in  cases  of 
acute  and  chronic  ulceration  of  the  bowels  and 
lungs,  and  also  of  ulcerative  stomatitis.  In  fact, 
he  regards  these  gonococci  (to  use  his  own  ex- 
pression) as  a  sort  of  pathological  "  sappers  and 
miners."  But  Dr.  Eklund  has  also  discovered  in 
pus  and  the  superficial  exudations  of  the  inflamed 
urethral  mucous  membrane  an  entirely  new  spe- 


GONORRHCEA.  309 

cies  of  parasite,  which  he  denominates  ediophyton 
didi/odes.  This,  like  all  similar  microbes,  is  prop- 
agated by  the  rapid  and  simultaneous  extension 
of  a  vast  network  of  mycelium-filaments  into  the 
glands,  the  lacunae,  and  the  ultimate  cellules  of 
the  affected  structure. 

It  will  be  seen  from  the  above  that  Dr.  Belfield 
is  not  quite  right  in  his  assertion  that  "  The  re- 
ports have  been,  with  one  exception,  unanimous 
in  corroborating  Neisser's  assertion  in  all  its  de- 
tails"  (Cartwright  Lectures,  /.  c.  p.  253).  More- 
over, it  may  be  questioned  whether  in  the  array 
of  names  presented  there  may  not  be  some  who 
have  not  given  sufficient  attention  to  the  study  of 
bacterial  organisms  to  give  much  weight  to  their 
assertion  that  the^  "gonococcm  "  of  Neisser  presents 
distinct  morphological  characters. 

Krause  also  found  that  rabbits,  cats,  and  mice 
were  insusceptible ;  but,  in  the  case  of  four  new- 
born rabbits,  successful  results  were  obtained  by 
inoculations  on  the  conjunctiva  with  material 
from  a  pure  culture. 

Not  having  the  original  memoir  of  this  author 
at  hand,  the  writer  does  not  feel  justified  in  offer- 
ing an  opinion  as  to  the  scientific  value  of  the 
results  recorded.  But  it  must  be  conceded  that 
the  exactions  of  science  demand  (a)  that  rabbits 
of  the  same  age  be  inoculated  in  the  same  man- 
ner with  pus  from  other  sources  —  not  virulent; 
(b)  that  the  experiment  be  successfully  repeated ; 
and  (c)  that  the  virulent  nature  of  the  inflamma- 


310  BACTERIA   IX  INFECTIOUS   DISEASES. 

tion  produced  be  proved  by  successive  inoculations 
on  the  conjunctivas  of  a  series  of  young  rabbits. 

In  1880  "  Bokai  cultivated  the  cocci  from  secretions 
of  (a)  an  acute  conjunctival  blenorrhcea  which  was  a 
few  days  old ;  (6)  an  acute  conjunctival  blenorrhoea  of 
the  second  week;  (e)  acute  gonorrhoea  of  the  first, 
second,  and  third  weeks.  Bokai  does  not  describe  his 
exact  method  of  cultivation,  but  contents  himself  with 
saying,  that  it  was  done  in  such  a  way  as  to  preclude 
the  presence  of  other  organisms.  Each  of  his  culture- 
fluids  after  two  or  three  weeks  was  swarming  with  micro- 
cocci,  which  were  in  every  way  identical  with  those 
described  by  Neisser.  With  these  cultivated  micrococci 
infection  experiments  were  made  on  the  human  ure- 
thral  mucous  membrane.  Six  students,  whose  self- 
sacrifice  in  the  interest  of  science  is  ever  to  be  com- 
mended, offered  themselves  as  subjects  of  experiment. 
In  three  cases  an  acute  urethral  gonorrhoea  witli  all 
the  well-known  symptoms  was  caused."  (Quoted  from 
Keyser.) 

The  fact  that  no  details  are  given  as  to  the 
method  of  cultivation,  and  that  the  experimenter 
is  not  known  as  an  expert  in  investigations  of  this 
kind,  leaves  ground  for  doubt  as  to  whether  pure 
cultures  were  used  in  this  experiment ;  and  there 
is  also  room  for  the  ungenerous  suspicion  that  the 
three  victims  may  have  contracted  the  disease  in 
the  usual  way.  Moreover,  the  statement  that  the 
culture-fluids  were  swarming  with  micrococci  after 
two  or  three  weeks  is  contrary  to  the  ivsults  ob- 
tained in  a  large  number  of  experiments  made  by 
the  writer.  In  every  instance  the  micrococci  mul- 


GONOKRHCEA.  311 

tiplied  abundantly  in  a  culture-fluid  during  the 
first  twenty-four  hours  after  it  was  inoculated  with 
gonorrhoeal  pus.  But  after  forty-eight  hours  all 
development  ceased,  in  consequence  of  the  pabu- 
lum being  exhausted,  and  the  micrococci  fell  to 
the  bottom  of  the  flask. 

"  In  September,  1882,  Bockhart  published  his  experi- 
ment- in  inoculating  the  gonococci  on  the  sound  human 
urethra!  mucous  membrane.  His  description  leaves  noth- 
ing to  be  desired  in  point  of  clearness.  The  subject  of 
the  experiment  was  a  forty-six-year-old  paralytic,  com- 
pletely anaesthetic,  whose  death  was  expected  daily. 
The  material  used  for  infection  consisted  of  gonococci 
grown  in  fresh  infusion  of  gelatine  through  four  gen- 
erations. 

"  The  urethra  of  the  person  experimented  upon  was 
previously  perfectly  sound.  Forty-eight  hours  after  in- 
jection there  appeared  at  the  meatus  urinarius  a  slight 
redness,  and  on  pressure  a  small  quantity  of  mucous  se- 
cretion could  be  obtained.  The  symptoms  increased, 
and  on  the  sixth  day  a  typical  gonorrhoea  was  formed, 
which  increased  in  severity  up  to  the  twelfth  day,  when 
the  man  died.  During  the  whole  time  the  characteristic 
gonococci  were  found  in  the  abundant  secretions." 
(Quoted  from  Keyser.) 

The  criticism  which  the  writer  feels  called  upon 
to  make  in  this  case,  which  is  thought  by  Keyser 
to  be  very  convincing,  is  that  a  series  of  four  suc- 
cessive cultures  is  not  sufficient  to  insure  the  ex- 
clusion of  the  original  material  when  the  cultivation 
is  conducted  upon  a  solid  substratum.  As  multiplica- 
tion only  occurs  upon  the  surface  of  the  culture- 


312  BACTERIA  IN  INFECTIOUS   DISEASES. 

medium,  the  material  used  to  inoculate  culture 
No.  1  is  not  diluted  in  a  series  of  cultures,  as  in 
the  method  described  on  page  238,  and  we  have 
no  longer  the  astonishing  array  of  figures  there 
given  to  show  the  practical  exclusion  of  a  hypo- 
thetical, non-living  virus.  When  we  consider  that 
material  from  the  surface  of  culture  No.  1  is  trans- 
ferred to  the  surface  of  culture  No.  2,  and  so  on, 
we  must  admit  the  possibility  that  some  of  the 
original  material  may  have  been  transferred  to 
culture  No.  4. 

This  source  of  error  was  excluded  in  the  follow- 
ing experiments : — 

"  The  pus,  from  which  the  cultures  used  in  these 
experiments  were  started,  was  taken  from  cases  [of 
gonorrhoea  in  the  male]  in  the  acute  stage  of  the  dis- 
ease, and  which  had  not  been  subjected  to  any  local 
treatment. 

"Uxp.No.4  (July,  1882).  — Made  by  Dr.  Hirsch- 
felcler  with  material  furnished  by  the  writer.  A  cul- 
ture fluid,  fifteenth,  containing  the  micrococcus  of 
gonorrhceal  pus,  was  introduced  into  the  urethrse  of 
three  patients  in  the  city  and  county  hospital,  upon 
small  wads  of  cotton  which  were  thoroughly  moistened 
with  the  fluid,  and  left  in  situ  for  fifteen  minutes. 

"Case  1.  —  J.  D.  has  been  in  bed  for  about  nine 
months ;  caries  of  the  vertebrae. 

^Case  2. —  J.  B.,  colored;  syphilitic  paralysis. 

"Case  3.  —  D.  M.,  in  bed  some  time;  aneurism  of 
the  abdominal  aorta.  The  result  was  entirely  nega- 
tive. 

"Exp.  No.  5  (August,  1882).— A  fresh  culture, four- 
teenth, from  another,  and  recent,  case  was  introduced 


GONORRHOEA.  313 

in  the  same  manner  into  the  urethra  of  J.  D.,  subject  of 
previous  experiment.  Result  negative. 

kt  Exp.  No.  6  (August,  1883).  —  A  fresh  culture,  thir- 
teenth, was  introduced  into  the  urethra  of  W.  B. 
Result  negative.  .  .  . 

"  Exp.  No.  15  (October  5th,  1882).  —  A  pure  culture 
of  the  micrococcus  of  gonorrhoeal  pus  (the  thirtieth  cul- 
ture, or  above),  was  introduced  into  the  urethrse  of  two 
healthy  men  [G.  M.  S.  and  V.  D.],  by  means  of 
pledgets  of  cotton  wool  soaked  in  the  fluid,  which  were 
left  in  situ  for  fifteen  minutes.  Result  entirely  nega- 
tive." 

A  somewhat  extended  account  has  been  given 
of  these  experiments  relating  to  the  etiology  of 
gonorrhoea,  because  it  is  deemed  a  matter  of  great 
scientific  importance  to  determine,  in  a  definite 
manner,  the  relation  of  the  micrococcus,  demon- 
strated to  be  constantly  present,  to  the  infective 
virulence  of  the  material  containing  it.  It  is  evi- 
dent that  if  a  single  infectious  disease  is  shown  to 
be  independent  of  all  micro-organisms,  no  general- 
ization in  favor  of  the  parasitic-germ  theory  will  be 
possible,  and  the  etiology  of  each  infectious  disease 
must  be  worked  out  separately  by  the  experimental 
method. 

In  the  disease  under  consideration,  it  is  evident 
that  the  contradictory  results  reported  call  for 
further  investigation ;  and,  notwithstanding  the 
negative  results  which  have  attended  his  own 
experimental  inoculations,  and  the  fact  that  the 
"  gotwcoccus  "  of  Neisser  has  not  distinctive  mor- 
phological characters,  the  writer  will  be  very  ready 


314  BACTERIA   IN  INFECTIOUS  DISEASES. 

to  admit  the  essential  etiological  role  of  this  micro- 
coccus  whenever  it  is  demonstrated  that  a  pure 
culture  introduced  into  the  urethra  of  man,  or  into 
the  conjunctival  sac  of  young  rabbits,  is  followed 
by  a  specific  inflammation,  as  shown  by  the  viru- 
lent character  of  the  purulent  discharge  which 
attends  it. 

HYDROPHOBIA.  —  That  illustrious  men  are  not 
always  infallible,  is  shown  by  the  error  into  which 
Pasteur  fell  in  ascribing  to  a  micrococcus  com- 
monly found  in  human  saliva,  the  power  of  pro- 
ducing hydrophobia.  The  experiments  which  led 
to  this  conclusion,  which  was  communicated  to  the 
French  Academy  in  1881,1  were  made  with  the 
saliva  of  a  child,  five  years  of  age,  which  died  from 
hydrophobia  in  one  of  the  hospitals  of  Paris,  De- 
cember llth,  1880.  This  child  had  been  bitten  in 
the  face,  a  month  previously,  by  a  mad  dog.  Four 
hours  after  death,  a  little  buccal  mucus,  gathered 
by  means  of  a  brush,  was  injected  into  two  rabbits. 
These  rabbits  were  found  dead  December  13th. 
Other  rabbits  were  inoculated  with  the  blood  of 
these,  and  death  occurred  even  more  rapidly. 
Successive  inoculations,  repeated  many  times, 
gave  the  same  result.  The  rabbits  showed  at 
the  autopsy  the  same  lesions.  (These  will  be  de- 
scribed in  the  account  given  of  induced  septicaemia 
in  the  rabbit,  p.  359.) 

According   to   Pasteur,   death   is   produced   by 

1  Comptes  rendus,  XCII.  p.  159. 


HYDROPHOBIA.  315 

the  injection  of  blood  or  of  saliva,  and  the  blood 
of  the  animal  inoculated  contains  a  microscopic 
organism  having  very  curious  properties.  Dogs 
inoculated  with  the  "  new  disease  "  fall  sick  im- 
mediately, and  usually  die  in  a  few  days,  without 
manifesting  any  of  the  true  symptoms  of  hydro- 
phobia. Rabbits  inoculated  from  mad  dogs  have 
a  variable  period  of  incubation,  so  that  the  disease 
in  question  cannot  be  identical  with  hydrophobia. 
Pasteur,  then,  did  not  commit  the  error  of  de- 
scribing this  "new  disease"  as  hydrophobia,  but 
he  made  the  erroneous  assumption  that  the  saliva 
of  the  child  was  virulent  because  it  had  died  of 
hydrophobia,  whereas  the  writer  has  shown  that 
the  same  infectious  disease  results  from  the  injec- 
tion into  the  subcutaneous  connective  tissue  of 
rabbits  of  normal  human  saliva.  This  fact  was 
first  disclosed  by  an  experimental  injection  of 
0.5  c.c.  of  my  own  saliva,  made  in  New  Orleans, 
La.,  September  29th,  1880,  nearly  three  months 
prior  to  the  death  of  the  child  from  which  Pasteur 
obtained  saliva  for  his  experiments ;  and  my  first 
experiments  in  New  Orleans  were  followed  by 
many  others  made  in  Philadelphia  during  the 
month  of  January,  1881,  and  in  Baltimore  during 
the  months  of  June  and  July  of  the  same  year. 

Pasteur  soon  became  convinced  that  the  microbe 
of  his  "  new  disease "  had  nothing  to  do  with 
hydrophobia,  and  he  has  recently1  communicated 
additional  flicts  of  the  greatest  importance  bearing 

l   Comptes  rendus,  XCV.  pp.  1187-1192. 


316  BACTERIA  IN  INFECTIOUS  DISEASES. 

upon  the  etiology  of  this  disease.     These  facts  he 
has  summarized  as  follows :  — 

"I.  The  silent  (la  rage  mue)  and  furious  forms  of 
rabies  proceed  from  the  same  virus.  Indeed,  we  have 
found  experimentally  that  one  form  may  give  rise  to  the 
other. 

"II.  Nothing  is  more  varied  than  the  symptoms  of 
rabies.  Each  case  has,  so  to  speak,  its  own  peculiar 
symptoms,  the  special  characters  of  which,  there  is 
reason  to  believe,  depend  upon  the  particular  part  of 
the  nervous  system,  of  the  brain,  or  of  the  spinal  mar- 
row, where  the  virus  locates  itself  and  multiplies. 

"  III.  The  virus  is  associated  in  the  saliva  of  a  rabid 
animal  with  various  microbes ;  and  this  saliva  may 
cause  death,  by  inoculation,  in  three  different  ways:: — 

"  By  the  new  microbe  which  we  have  made  known 
under  the  name  of  the  microbe  of  saliva; 

"  By  the  excessive  development  of  pus  ; 

"  By  rabies. 

"  IV.  The  medulla  oblongata  of  a  person,  or  of  one 
of  the  lower  animals,  dead  from  rabies,  is  always  vir- 
ulent. 

"  V.  The  virus  of  rabies  is  not  only  found  in  the  me- 
dulla oblongata,  but  also  in  the  entire  brain  or  a  portion 
thereof. 

"  It  is  also  found  localized  in  the  spinal  marrow,  and 
often  in  every  portion  of  it. 

"  The  virulence  of  the  spinal  marrow  is  quite  equal 
to  that  of  the  medulla  oblongata  or  of  the  brain ;  and 
this  is  true  of  the  inferior  as  well  as  of  the  superior 
portions. 

"So  long  as  the  brain  and  spinal  marrow  are  not 
invaded  by  putrefaction  this  virulence  persists.  At  a 
temperature  of  about  12°  C.  we  have  been  able  to  pre- 


INTERMITTENT  FEVER.  317 

serve  the  virulence  of  the  brain  of  a  rabid  animal  for 
three  weeks. 

44  VI.  In  order  to  produce  rabies  with  certainty  and 
rapidity,  it  is  necessary  to  inoculate  the  surface  of  the 
brain,  in  the  cavity  of  the  arachnoid,  by  means  of 
trephining. 

44  The  same  result  is  obtained  by  introducing  the 
virus  directly  into  the  blood. 

44  These  methods  of  inoculation  frequently  give  rise  to 
the  disease  at  the  end  of  six,  eight,  or  ten  days. 

44  VII.  Rabies  communicated  by  introducing  the  virus 
into  the  blood  very  often  presents  characters  quite  dif- 
ferent from  those  of  furious  rabies,  resulting  from  a  bite 
or  from  inoculation  upon  the  surface  of  the  brain,  and 
it  is  probable  that  many  cases  of  silent  rabies  have 
escaped  observation.  In  the  cases  which  may  be  denom- 
inated medullary,  prompt  paralyses  are  frequent,  furor 
is  often  absent,  and  the  rabid  barkings  are  rare ;  on  the 
contrary,  the  itching  is  sometimes  terrible. 

44  The  details  of  our  experiments  lead  us  to  believe 
that,  in  the  method  by  intravenous  injection,  the  spinal 
marrow  is  first  attacked ;  that  is  to  say,  that  the  virus 
first  fixes  itself  and  multiplies  in  this  locality." 

INTERMITTENT  FEVER.  —  The  limits  of  the  pres- 
ent volume  do  not  admit  of  an  extended  account 
of  the  experimental  evidence  which  has  been  ad- 
vanced in  favor  of  the  parasitic-germ  theory  as 
regards  the  etiology  of  the  malarial  fevers.  The 
fact  that  the  malarial  poison  is  evolved  under  cir- 
cumstances which  favor  the  development  of  low 
organisms,  and  that  its  production  has  been  pretty 
definitely  proved  to  be  associated  with  the  decom- 
position of  organic  material  of  vegetable  ori- 


318  BACTERIA  IN  INFECTIOUS  DISEASES. 

gin  —  which  has  been  proved  to  depend  upon 
the  presence  of  bacterial  organisms,  has  led  many 
physicians  confidently  to  anticipate  that  a  malarial 
germ  would  be  found  in  the  bodies  of  those  suffer- 
ing from  malarial  poisoning  ;  and  since  the  demon- 
stration of  the  anthrax  bacillus,  and  the  spirillum 
of  relapsing  fever,  it  seems  to  have  been  rather 
hastily  assumed  that  all  disease  germs  are  to  be 
sought  especially  in  the  blood.  In  intermittent 
fever,  however,  it  would  seem,  a  priori,  that  the 
hypothetical  parasite  would  not  be  likely  to  find  a 
suitable  culture-medium  in  the  blood  of  a  living 
animal  ;  (a)  because  its  normal  habitat  is  in 
swamps,  where  its  development  is  associated  with 
the  decomposition  of  vegetable  matter ;  and 
(£)  because,  so  far  as  we  know,  parasitic  micro- 
organisms, which  multiply  freely  in  the  blood  of 
living  animals,  produce  infectious  diseases  com- 
municable from  one  individual  to  another,  whereas 
we  have  no  evidence  that  this  ever  occurs  in  the 
paludal  fevers.  Conditions  more  nearly  approach- 
ing those  which  favor  the  development  of  the 
poison  external  to  the  body  may,  however,  be 
found  in  the  alimentary  canal,  and  we  may  sup- 
pose that  the  germ  locates  itself  here.  Or  we 
may  admit  the  possibility  that  its  action  is  re- 
stricted to  the  production  of  a  volatile  chemical 
poison  which  is  evolved  as  a  result  of  its  vital 
activity  in  the  localities  where  it  abounds  external 
to  the  body;  and  that  this  infects  the  atmosphere 
in  the  vicinity,  and  produces  malarial  poisoning  in 


INTERMITTENT  FEVER.  319 

those  who  respire  this  atmosphere.  But  this  is 
speculation,  and  cannot  stand  before  the  results 
of  exact  experiments.  Let  us  then  briefly  review 
these  results,  or  at  least  those  which  have  been 
most  recently  reported,  and  seem  most  worthy  of 
attention. 

Passing  by  the  researches  of  Salisbury  and  other 
claimants  to  the  honor  of  having  discovered  the 
malarial  parasite,  we  come  at  once  to  the  investi- 
gations of  Klebs  and  Tommasi-Crudeli,  made  in 
the  vicinity  of  Rome,  and  as  a  result  of  which 
they  announced  in  1879  the  discovery  of  the 
Bacillus  malarice. 

The  evidence  in  favor  of  this  discovery  is  stated 
so  concisely  in  an  editorial  in  "  The  Medical 
News " l  that  the  writer  takes  the  liberty  of 
quoting  from  this  for  his  present  purpose :  — 

"  These  observers  found  in  the  earth  of  malarial  dis- 
tricts, in  Italy,  numerous  shining  oval  and  mobile  spores, 
.95  of  a  micro-millimetre  in  the  longer  diameter.  They 
were  able  to  cultivate  these  spores  in  the  animal  body 
as  well  as  in  culture  experiments,  and  the  animals  in- 
fected by  them  exhibited  not  only  the  clinical  course  of 
malarial  disease  as  seen  in  man,  but  also  the  post  mortem 
appearances ;  while  the  bacillus  was  also  found  in  the 
blood  of  such  animals,  taken  after  death.  The  spores 
develop  in  the  animal  body,  as  well  as  in  culture-experi- 
ments, into  long  threads,  which  are  at  first  homogeneous, 
but  later  divide,  while  new  spores  develop  in  the  interior 
of  the  segments.  The  position  of  the  spores,  which  are 

i  Philadelphia,  January  13th,  1883,  Vol.  XLII.  No.  2,  p.  41. 


320 


BACTERIA   IN  INFECTIOUS   DISEASES. 


found  either  at  the  poles,  or  in  the  middle  of  the  seg- 
ment, serves  as  a  mark  of  distinction  between  this  and 
other  pathological  bacilli. 

u  Following  Klebs  and 
Tommasi-Crudeli,  Mar- 
chiafava  and  Cuboni,  in 
Italy,1  studied  the  blood 
of  men  ill  with  malaria. 
In  this  they  found  spores 
and  bacilli  which  they 
declared  to  be  identical 
with  those  described  by 
the  former.  The  spores 
included  in  the  white 
blood  -  corpuscles  were 

Bacillus  malaria  in  blood  drawn  during  Sometimes  SO  numerous 
life  from  the  spleen  of  a  person  suffering 
from  malarial  fever.  (From  Cuboni  and 
Marchiafava,  in  Klebs'  Archiv,  etc.,  1881.) 
N.  B.  These  bacilli  were  found  in  one  case 
only. 


Fig.  14. 


as  to  seem  to  fill  them 
completely.  Similar  stud- 
ies on  malarial  patients 
by  Lanzi,  and  again  by 
Peroncito,  led  to  the  same  conclusions. 

"  Succeeding  these,  Marchand  published  in  Virchow's 
4  Archiv ' 2  some  observations  really  made  in  1876, 
whence  he  concluded  that  there  exists  in  the  blood,  in 
the  cold  stage  of  intermittent  fever,  mobile  arid  flex- 
ible rods,  presenting  slight  swellings  at  their  ends,  and 
sometimes  also  at  the  middle.  These  end-swellings  he 
thought  also  might  be  of  the  nature  of  spores. 

"  More  recent  still  are  the  elaborate  experiments  of 
Professor  Ceri,  of  Camerino,  Italy,  published  in  the 
'Archiv  fur  experimentelle  Pathologic.'3  These  con- 

1  Archiv  fur  experimentelle  Pathologic,  Vol.  XIII. 

2  Vol.  LX XX VIII.  p.  104,  April,  1882. 
«  Vols.  XV.  and  XVI.  1882. 


INTERMITTENT  FEVER.  321 

sisted  of  culture-experiments  with  organisms  found  in 
malarial  and  other  soils,  of  experiments  on  animals,  and 
culture-experiments  with  quinine.  They  resulted  in 
proving  that  the  spores  could  be  cultivated,  —  Ceri 
applying  the  term  natural  germs  to  those  found  in  the 
atmosphere  and  soil,  and  artificial  germs  to  those  which 
result  from  their  culture  ;  that  animals  could  be  infected 
by  their  injection  into  the  blood,  though  to  a  less  degree 
by  the  cultivated  than  by  the  natural  germs,  the  former 
growing  weaker  in  successive  generations ;  and  that 
the  infecting  properties  could  be  retarded  by  the  appli- 
cation of  heat  to  culture-fluids,  and  the  introduction  of 
quinine  into  them,  certain  degrees  of  the  former  and 
strengths  (1 :  800)  of  the  latter  making  the  culture 
of  the  spores  impossible,  and  arresting  the  putrid  fer- 
mentation induced  by  them.  The  practical  application 
of  these  facts  is  self-evident. 

"  Finally  the  opportunity  has  recently  been  present- 
ed to  Dr.  Franz  Ziehl  to  test  these  results  clinically  l 
in  three  typical  cases  of  malaria,  in  all  of  which  the 
spleen  was  enlarged.  In  all  three  the  bacilli  above  de- 
scribed were  found  in  the  blood  taken  from  any  part  of 
the  body  by  the  prick  of  a  needle,  and  examined  in  the 
fresh  state,  or  dried  in  a  thin  layer  upon  a  cover-glass, 
by  simply  passing  the  latter  over  a  flame.  These  have 
been  preserved  by  Dr.  Ziehl  for  three  months  without 
undergoing  any  change. 

44  The  bacilli  thus  observed  were  of  different  lengths, 
but  usually  were  from  one-fourth  to  the  entire  diameter 
of  a  red  corpuscle.  The  majority  of  those  measured 
were  about  4  micro-millimetres  long  and  .7  broad.  Their 
ends  were  swollen  and  roundish." 

The  evidence  as  here  stated  certainly  seems  very 

1  Deutsche  medizinische  Wochenschrift,  Nov.  25,  1882. 
21 


322 


BACTERIA  IN  INFECTIOUS  DISEASES. 


Fig  15 


complete,  and  the  writer 
freely  admits  that  the  nega- 
tive results  which  he  report- 
ed after  an  attempt  to  repeat 
the  experiments  of  Klebs  and 
Tommasi-Crudeli,  made  under 
the  auspices  of  the  National 
Board  of  Health  in  New  Or- 

l™™>    du™8    tllG    Slimmer    of 

1880.    CattDOt     be     given 
° 


The  Bacilli  malaria  as  seen 
in  blood  obtained  from  a  pa- 
tient  seized  with  intermittent  m 

fever,  taken  during  the  chill.      WClght     aS     OppOSed     to 

-^  , 

But  the 


(From  Tommasi-Crudeli.) 


. 

positive  statements. 

fact  that  no  confirmation  has  yet  come  from  Eng- 
lish or  American  sources  during  the  time  which 
has  elapsed  since  the  discovery  of  Klebs  and 
Tommasi-Crudeli  was  announced,  constitutes  nega- 
tive evidence  of  a  much  stronger  character.  The 
Bacillus  malaria,  according  to  all  accounts,  should 
be  much  easier  to  recognize  than  Koch's  bacillus  of 
tuberculosis,  which  has  already  been  seen  by  numer- 
ous physicians  in  nearly  every  large  city  in  this 
country  and  in  Europe.  But  who  on  this  side  of 
the  Atlantic  has  seen  the  Bacillus  malariw?  Yet 
malarial  fevers  are  widespread,  and  a  microscope 
is  to  be  found  in  nearly  every  physician's  office. 
The  writer  has  searched  faithfully  for  this  bacillus 
in  the  blood  of  patients  in  the  Charity  Hospital, 
New  Orleans,  selected  for  him  by  Professor  Bemiss 
as  well-marked  cases  of  malarial  fever,  but  admits 
that  he  has  not  sought  it  in  blood  from  the  spleen, 
or  in  that  drawn  during  a  chill,  except  in  two  or 


INTERMITTENT   FEVER,  323 

three  instances.  He  is  therefore  anxious  to  make 
more  extended  researches  whenever  the  opportu- 
nity may  offer,  and  will  not  fail  to  report  promptly 
any  future  observations  more  in  correspondence 
with  those  of  the  German  and  Italian  investigators 
named. 

In  the  report  of  the  experimental  investigation 
referred  to,  the  following  summary  statement  is 
made  :  — 

"  Among  the  organisms  found  upon  the  surface  of 
swamp-mud,  near  New  Orleans,  and  in  the  gutters 
within  the  city  limits,  are  some  which  closely  resemble, 
and  perhaps  are  identical  with,  the  Bacillus  malarice  of 
Klebs  and  Tommasi-Crudeli ;  but  there  is  no  satisfactory 
evidence  that  these  or  any  of  the  other  bacterial  organ- 
isms found  in  such  situations,  when  injected  beneath  the 
skin  of  a  rabbit,  give  rise  to  a  malarial  fever  correspond- 
ing with  the  ordinary  paludal  fevers  to  which  man  is 
subject. 

44  The  evidence  upon  which  Klebs  and  Tommasi-Cru- 
deli have  based  their  claim  of  the  discovery  of  a  Bacillus 
malarice  cannot  be  accepted  as  sufficient ;  («)  because 
in  their  experiments  and  in  my  own  the  temperature 
curve  in  the  rabbits  experimented  upon  has  in  no  case 
exhibited  a  marked  and  distinctive  paroxysmal  char- 
acter; (£>)  because  healthy  rabbits  sometimes  exhibit 
diurnal  variations  of  temperature  (resulting  apparently 
from  changes  in  the  external  temperature)  as  marked 
as  those  shown  in  their  charts  ;  (c)  because  changes  in 
the  spleen  such  as  they  describe  are  not  evidence  of 
death  from  malarial  fever,  inasmuch  as  similar  changes 
occur  in  the  spleens  of  rabbits  d,ead  from  septicjemia 
produced  by  the  subcutaneous  injection  of  human  saliva; 


324  BACTERIA  IN  INFECTIOUS  DISEASES. 

(dT)  because  the  presence  of  dark-colored  pigment  in  the 
spleen  of  a  rabbit  cannot  be  taken  as  evidence  of  death 
from  malarial  fever,  inasmuch  as  this  is  frequently  found 
in  the  spleens  of  septicsemic  rabbits. 

"  While,  however,  the  evidence  upon  which  Klebs 
and  Tommasi-Crudeli  have  based  their  claim  to  a  dis- 
covery is  not  satisfactory,  and  their  conclusions  are 
shown  not  to  be  well  founded,  there  is  nothing  in  my 
researches  to  indicate  that  the  so-called  Bacillus  malarice, 
or  some  other  of  the  minute  organisms  associated  with 
it,  is  not  the  active  agent  in  the  causation  of  malarial 
fevers  in  man.  On  the  other  hand,  there  are  many  cir- 
cumstances in  favor  of  the  hypothesis  that  the  etiology 
of  these  fevers  is  connected,  directly  or  indirectly,  with 
the  presence  of  these  organisms  or  their  germs  in  the 
air  and  water  of  malarial  localities." 

It  will  be  seen  that  I  am  not  able  to  agree  with 
the  editorial  above  quoted  in  the  statement,  that 
"the  animals  infected  by  them"  —  i.  e.,  the  spores 
of  Bacillus  malarice  — "  exhibited  not  only  the 
clinical  course  of  malarial  disease  as  seen  in  man, 
but  also  the  post  mortem  appearances. "  On  the 
other  hand,  I  do  not  find  in  the  temperature-charts 
published  by  Klebs  and  Tommasi-Crudeli  in  their 
original  report,  and  copied  by  me  in  my  report 
referred  to,  satisfactory  evidence  of  the  production 
of  a  fever  characterized  by  regularly  recurring 
paroxysms,  like  the  ordinary  paludal  fevers  in 
man ;  nor  do  I  consider  the  post  mortem  appear- 
ances sufficiently  characteristic  to  warrant  the  infer- 
ence that  these  animals  died  of  a  fever  identical 
with  the  malarial  fevers  to  which  the  human  race 


INTERMITTENT  FEVER.  325 

is  so  subject ;  especially  in  view  of  the  fact,  that 
infection  did  not  occur  in  the  natural  way,  that  the 
rabbit  is  very  subject  to  various  forms  of  septi- 
caemia, and  that  prior  to  these  experiments  no  evi- 
dence had  ever  been  presented  to  show  that  the 
rabbit  -experiences  any  harm  from  respiring  an 
atmosphere  charged  with  malaria. 

Professor  Ceri,  however,  claims  to  have  produced 
in  rabbits  intense  febrile  paroxysms  of  a  decidedly 
intermittent  type,  and  continuing  for  a  long  period,  by 
the  hypodermic  injection  of  artificially  cultured 
malarial  soil  exposed  for  ten  days  to  a  temperature 
of  35°  to  40°  C. 

This  is  a  very  definite  statement,  and,  if  sup- 
ported by  temperature-charts  showing  the  fact, 
would  have  great  weight. 

In  a  recent  report  (March  18,  1883)  to  the 
Italian  Minister  of  Agriculture,  Tommasi-Crudeli 
refers  to  the  production  of  intermittent  (?)  fevers 
in  the  lower  animals  by  the  subcutaneous  injection 
of  the  blood  of  malarial-fever  patients,  and  states 
that  he  made  extensive  preparations  to  continue 
his  experiments  in  this  direction  during  the  year 
1882  ;  but  he  was  unable  to  carry  out  his  inten- 
tion for  the  reason  that  not  a  single  case  of  perni- 
cious fever  was  received  during  that  period  into 
the  Koman  hospitals.1 

Here,  then,  we  have  a  confession  which  makes  it 
evident  that  the  pernicious  fever,  ascribed  to  malaria, 

1  Quoted  from  a  paper  in  the  Med.  Record  of  August  18,  1883,  by  Dr. 
C.  P.  Russell. 


326  BACTERIA  IN   INFECTIOUS  DISEASES. 

by  the  author  referred  to,  differs  from  ordinary 
malarial  fevers  —  intermittents  and  remittents  — 
which  also  prevail  in  Italy,  in  the  essential  par- 
ticular that  it  is  an  infectious  disease,  and  may  be 
transmitted  to  the  lower  animals  ;  as  well  as  in  the 
fact  that  it  is  a  continued  rather  than  a  paroxysmal 
fever. 

The  writer  has  long  suspected  that  the  continued 
pernicious  fevers  of  the  Roman  Campagna,  and  of 
other  parts  of  Italy,  differ  essentially  from  the  or- 
dinary intermittents  and  remittents  of  this  country, 
and  that,  while  there  is  undoubtedly  a  malarial 
element,  in  a  certain  proportion  of  the  cases  at 
least,  there  is  another  etiological  factor  to  which 
the  continued  and  pernicious  form  of  development 
manifested  by  the  morbid  phenomena  must  be 
ascribed.  We  know  that  malaria  may  be  associ- 
ated with  the  specific  poisons  of  typhoid  and  of 
yellow  fevers  in  such  a  way  as  to  produce  atypical 
forms  of  these  diseases,  and  it  seems  not  impro- 
bable that  the  Roman  fever  is  in  truth  one  of  these 
mixed  or  hybrid  forms  of  disease.  In  this  case 
the  bacillus  of  Klebs  and  Tommasi-Crudeli,  if  it 
has  any  etiological  import,  is  probably  the  factor 
to  which  the  continued  and  pernicious  form  of  this 
fever  must  be  ascribed,  rather  than  the  malarial 
germ,  which  the  authors  named  had  undertaken 
to  discover. 

Professor  Ceri's  experiments  relating  to  the 
germicide  power  of  quinine  are  extremely  impor- 
tant and  interesting.  But  it  is  well  to  remember 


INTERMITTENT  FEVER.  327 

that,  if  a  dose  of  ten  grains  passed  at  once  into 
the  blood  of  an  adult  weighing  one  hundred  and 
sixty  pounds,  the  proportion  which  it  would  bear 
to  the  whole  mass  of  blood  in  the  body  (estimated 
at  twenty  pounds)  would  be  only  1 : 11,520;  whereas 
Professor  Ceri's  experiments  lead  him  to  the  con- 
clusion, "  that  the  muriate  of  quinine  in  the  pro- 
portion of  1 :  800  prevents  the  development  of  any 
infectious  germs."  1 

The  preventive  power  for  the  Bacillus  maZartce, 
however,  was  found  to  be  greater  than  this,  and  in 
a  series  of  eighteen  experiments  in  which  culture- 
solutions  were  infected  "  with  a  drop  of  blood  [con- 
taining the  Bacillus  malarias]  of  a  rabbit  into  which 
had  been  injected  cultures  of  malarial  soil,  the 
development  continued  absent  up  to  1 :  2,000,  and 
at  1  :  2.250  it  was  aseptic.  The  Bacillus  malarias 
did  not  develop  in  the  fertile  cultures,  which  con- 
tained only  vibriones." 

The  writer  is  not  disposed  to  underestimate  the 
value  of  these  researches,  but  in  a  spirit  of  scien- 
tific conservatism  would  remark  as  follows  :  — 

First. — Fowler's  solution  of  arsenic  also  cures 
intermittent  fever;  and  the  germicide  power  of 
this  remedy  is  practically  nil,  as  determined  by  the 
writer  in  a  series  of  experiments  in  which  the 
micrococcus  of  pus  served  as  a  test-organism.  In 
the  proportion  of  forty  per  cent  it  failed  to  kill 
this  organism.  Its  power  of  restricting  the  devel- 

1  Quoted  from  translation  by  Hugo  Engel  in  "  The  Medical  Times," 
Philadelphia,  Dec.  16,  1882,  p.  198. 


328  BACTERIA  IN  INFECTIOUS   DISEASES. 

opment  of  the  Bacillus  malarice  should  be  tested 
as  a  check  on  the  conclusions  which  may  be  too 
hastily  drawn  from  Professor  Ceri's  experiments 
with  quinine. 

Second.  —  It  is  not  impossible  that  the  pernicious 
malarial  fevers  of  Italy  may  differ  essentially  from 
the  ordinary  remittents  and  intermittents  of  this 
country,  and  that  their  continued  form  is  due  to  a 
septic  complication,  which  may  result  from  invasion 
of  the  blood  by  a  pathogenic  organism  peculiar  to 
that  country  or  to  the  tropical  and  semi-tropical 
regions  where  pernicious  fevers  are  most  prevalent. 

Third.  —  Fat-granules  are  found  in  the  white 
corpuscles  of  the  blood  of  yellow  fever,  —  which 
disease  resembles  the  pernicious  malarial  fevers  in 
many  particulars,  —  which  bear  so  strong  a  resem- 
blance to  the  spores  of  bacilli  that  a  mistake  might 
easily  be  made.1  (See  p.  425.)  Several  of  the 
observers  named  found  spores  "  included  in  the 
white  blood-corpuscles,  which  were  sometimes  so 
numerous  as  to  seem  to  fill  them  completely." 

Fourth.  —  No  great  significance  can  be  attached 
to  the  finding  of  bacterial  organisms  post  morion 
in  the  blood  and  tissues,  especially  in  warm  cli- 
mates, unless  the  examination  is  made  intntcdmldf/ 
after  death.  And  even  then  we  must  admit  the 
possibility  that  such  organisms  may  migrate  from 
the  intestine,  where  they  are  always  present  in 
abundance,  during  the  last  hours  of  life,  when  the 
circulation  is  feeble,  and  the  vital  resistance  of  the 

1  Compare  Fig.  3,  Plate  X.,  and  Fig.  3,  Plate  III. 


INTERMITTENT  FEVER.  329 

cells  intervening  between  the  lumen  of  the  intes- 
tine and  of  its  capillary  vessels  is  very  feeble,  or 
quite  lost. 

Finally.  —  The  writer's  observations  lead  him  to 
be  suspicious  as  regards  the  pathogenic  role  of  or- 
ganisms in  the  blood,  which  are  few  in  number  and 
require  diligent  search  for  their  demonstration. 
And  the  possibilities  of  accidental  contamination 
are  so  great,  when  a  drop  of  blood  is  drawn  from 
the  body  of  a  patient  with  the  greatest  possible 
precautions,  that  the  finding  of  a  rod  or  of  a 
sphere  supposed  to  be  a  bacillus  or  a  micrococcus 
requires  verification  by  the  finding  of  at  least 
several  more  rods  or  spheres  of  the  same  kind  in 
the  same  specimen  ;  and  by  the  use  of  staining 
reagents  and  the  test  of  cultivation. 

A  more  recent  discovery  than  the  Bacillus  mala- 
rice  of  Klebs  and  Tommasi-Crudeli  is  the  Oscillaria 
malaria*  of  Laveran  (1881).  This  discovery  is  also 
confirmed  by  Richard.  The  first-named  author 
says :  — 

"  There  exist  in  the  blood  of  patients  attacked  with 
malarial  fever  pigmented  parasitic  elements,  which  pre- 
sent themselves  under  three  principal  aspects.  .  .  . 

"  The  parasitic  elements  are  only  found  in  the  blood 
of  patients  sick  with  malarial  fever,  and  they  disappear 
when  quinine  is  administered. 

"  They  are  of  the  same  nature  as  the  pigmented 
bodies  which  exist  in  great  numbers  in  the  vessels  and 
organs  of  patients  dead  with  pernicious  fever,  and  which 
have  heretofore  been  described  as  melanotic  leuco- 
cytes." 


330  BACTERIA  IN  INFECTIOUS  DISEASES. 

These  parasites  are  described  as  being  some- 
what smaller  than  the  leucocytes  of  the  blood, 
as  sometimes  resting  and  sometimes  exhibiting 
amoeboid  movements,  and  as  sometimes  having 
three  or  four  long,  motile  filaments  attached, 
which  are  very  difficult  to  see  except  when  they 
are  in  motion.  They  contain  pigment  granules, 
commonly  arranged  in  a  circle.  Richard  states 
that  the  malarial  parasite  of  Laveran  invades  the 
red  blood-corpuscles,  where  it  is  first  seen  as  a 
minute  round  spot  upon  the  circumference.  In 
other  corpuscles  it  is  larger,  and  about  the  margin 
is  seen  a  circle  of  black  nodules.  In  others  still 
the  parasite  has  reached  such  a  size  that  only  a 
narrow,  transparent  zone  remains  between  its 
circumference  and  the  cell-wall  of  the  red  corpus- 
cle, and  no  trace  of  the  haemoglobin  remains. 
The  oscillaria  is,  however,  still  surrounded  by  a 
ring  of  black  nodules.  The  parasite  now  escapes 
into  the  blood-serum.  The  motile  filaments  de- 
scribed by  Laveran  are  also  referred  to  by  Rich- 
ard, who  states  that  in  some  cases  they  alone 
perforate  the  cell-wall  of  the  red  corpuscle,  which 
is  moved  about  in  a  peculiar  manner  by  their 
oscillations. 

The  presence  of  these  parasites  was  demon- 
strated in  the  blood  of  every  case  .  of  malarial 
fever  observed  by  Richard,  and  frequently  they 
were  very  numerous. 

We  shall  not  attempt  to  estimate  the  scientific 
value  of  these  observations,  but  would  remark 


LEPROSY.  331 

that  Laveran  and  Richard,  in  the.ir  researches, 
seem  not  to  have  encountered  the  Bacillus  malarice, 
although  the  announcement  of  its  discovery  had 
been  made  two  years  prior  to  the  date  of  their 
investigations,  and  should  have  prepared  them  to 
find  it  if  present  in  the  blood  of  malarial  cases 
studied  by  them. 

LEPROSY.  —  In  1879  Hansen,  in  a  report  to  the 
Medical  Society  of  Christiania  (Norway),  stated 
that  he  had  "  often,  indeed  generally,  found,  when 
seeking  for  them  in  leprous  tubercles,  small,  rod- 
shaped  bodies  in  the  cells  of  the  swelling."  These 
rods  were  not  found,  however,  in  blood  recently 
taken  from  leprous  patients.  Certain  brown  cells 
were  also  described  in  this  report  as  peculiar  to 
leprosy.  In  a  later  communication  (1880)  Han- 
sen  says :  — 

"I  have  by  this  preparation  [staining  with  methyl- 
violet]  obtained  confirmation  of  my  earlier  supposi- 
tion, that  the  large  brown  bodies,  after  all,  are  nothing 
else  than  either  masses  of  zoogloea,  or  collections  of 
bacilli  which  are  enclosed  in  cells.  By  looking  at 
Fig.  4  [Fig.  16],  which  represents  tumor-cells  treated 
with  osmic  acid,  drawn  from  preparations  made  in 
1873,  one  is  easily  able  to  form  an  idea  how  these  same 
cells,  by  a  constantly  increasing  number  of  small  rods, 
at  last  become  quite  overloaded,  and  thus  obtain  the 
appearance  of  being  filled  with  fine  granules,  since  the 
single  rods  cannot  then  be  distinguished.  .  .  . 

"  Since  writing  the  above  I  have  also  been  so  fortu- 
nate as  to  obtain  bacilli,  finely  colored,  in  a  section  of 
a  tubercle  hardened  in  absolute  alcohol.  .  Bacilli 


332  BACTERIA  IN  INFECTIOUS  DISEASES. 


Fig.  16. 

C«lla  from  leprous  tubercle  containing  the  Bacillus  lepree.    Copied  from  plate  illus- 
trating Ilansen's  paper  in  Quart.  J.  Micr.  Sci.,  Jan.  1880. 

are  found  in  all  parts  of  the  section,  either  singly,  or 
more  frequently  in  groups,  fully  corresponding  to  those 
occurring  in  the  cells.  I  furnish  a  drawing  of  two 
groups  taken  with  Zeiss's  immersion  system  ^  and  eye- 
piece No.  4."  (See  Fig.  17.) 

One  observer,  Kober,  claims  to  have  found  the 
bacillus  of  Hansen  in  the  blood  of  leprous  pa- 
tients; while  Edlund  ascribes  the  disease  to  a 
micrococcus  which  he  finds  in  the  blood,  as  well 
as  in  the  leprous  tubercles.  Neisser,  also,  says 
that  micrococci  are  always  present  in  the  epider- 
mis, although  he  confirms  Ilansen  as  to  the  pres- 


LEPROSY.  333 

ence  of  bacilli  in  the  leprous  tubercles,  and  also  in 
the  liver,  spleen,  testicles,  lymph-glands,  and  other  parts. 
( Query :  How  much  time  had  elapsed  between  the 
death  of  the  patients  and  the  autopsies.) 

According  to  Neisser :  — 

44  The  bacilli  have  the  form 
of  small,  slender  rods,  with  a 
length  about  half  the  diameter 
of  a  red  blood-corpuscle,  and 
about  four  times  as  long  as 
broad.  They  approach  most 
nearly  the  bacilli  connected 
with  the  septicaemia  of  the 
mouse,  but  are  not  so  fine." 
[According  to  Koch,  they  very  Fig.  17. 

Closely  resemble    the    bacillus   Of      Copied  from  Hansen's  paper  above 

tuberculosis.]  "  They  are  in- 
visible in  uncolored  sections,  but  beautifully  seen  when 
tinctured  with  fuchsin  and  gentian-violet.  Their  rela- 
tive position  and  distribution  vary  greatly,  according  to 
the  part  where  they  are  found.  They  lie  either  two 
or  three  behind  one  another,  apparently  forming  a  long, 
sometimes  curved,  thread ;  or  six  or  seven  lie  parallel 
to  one  another ;  or  large  numbers  are  associated  in  all 
directions  into  a  confused  mass,  which  is  only  with  diffi- 
culty resolved  into  its  elements.  At  a  later  stage  of 
the  leprosy  the  rods  break  up  into  granules ;  but 
whether  these  are  the  result  of  disintegration,  or  must 
be  regarded  as  spores,  is  doubtful.  The  bacilli  were 
found  in  greatest  quantities  in  the  skin ;  next  to  that, 
in  the  testicles ;  also  in  the  spleen  and  liver ;  they 
were  not  found  in  the  marginal  parts  of  the  lymph- 
canals  ;  the  kidneys  were  free  from  them."  1 

1  Quoted  from  Journal  of  the  Royal  Mier.  Society,  Ser.  II.  Vol.  I. 
Part  2,  December,  1881,  p.  928. 


334  BACTERIA  IN  INFECTIOUS   DISEASES. 

The  presence  of  these  bacilli  in  leprous  tuber- 
cles, etc.,  has  been  confirmed  by  several  observers 
in  addition  to  those  mentioned.  Recently  Dr. 
Thin,  an  experienced  microscopist  and  mycolo- 
gist,  has  reported  that  he  finds,  in  the  skin  of 
Chinese  lepers,  a  bacillus  of  the  size  and  form, 
and  same  staining  qualities,  as  that  described  by 
Hansen.1  It  is  said  that  the  bacillus  is  not  found 
in  the  anaesthetic  form  of  the  disease. 

The  writer  examined  the  blood  of  lepers  in  the 
Charity  Hospital,  New  Orleans,  during  the  sum- 
mer of  1880,  with  a  negative  result,  so  far  as  the 
direct  examination  was  concerned.  But  in  cul- 
ture-cells in  which  a  drop  of  blood,  protected  from 
the  external  air,  was  supplied  with  oxygen  from  a 
small  air-space,  hermetically  enclosed,  micrococci 
developed,  which  may  be  seen  in  the  heliotype  re- 
production of  a  photo-micrograph  made  from  such 
a  specimen,  Plate  II.  Fig.  3. 

Inasmuch  as  these  lepers  had  upon  the  face  and 
hands  ulcerated  tubercles,  the  pus  from  which 
was  doubtless  infested  with  micrococci,  very  little 
importance  was  attached  to  the  fact  that  micro- 
cocci  made  their  appearance  in  these  culture-cells. 
For  the  chances  of  accidental  contamination,  of  a 
drop  of  blood  drawn  from  the  finger,  by  micro- 
cocci  from  the  surface  of  the  body,  were  so  great 
as  to  give  but  little  value  to  the  culture-experi- 
ment, notwithstanding  the  fact  that  the  precaution 
was  taken  to  wash  the  finger  with  alcohol  before 

1  British  Medical  Journal,  Aug.  6,  1882,  p.  231. 


LEPROSY.  335 

making  the  puncture.  The  writer's  own  experi- 
ments have  since  shown  that  this  precaution  is 
probably  inadequate ;  for  the  micrococcus  of  pus 
is  not  killed  by  exposure  for  two  hours  to  25  per 
cent  alcohol. 

Up  to  the  present  time,  the  supposition  that  the 
bacillus  of  Hansen  bears  a  causal  relation  to  lep- 
rosy depends  for  its  support  entirely  upon  the  fact 
that  it  is  found  in  the  leprous  tubercles,  etc.  It 
is  not  well  established  that  these  bacilli  have  dis- 
tinctive morphological  characters  and  staining  re- 
actions. Indeed,  Koch  finds  that  they  closely 
resemble  his  bacillus  of  tuberculosis  in  both  these 
particulars.  But  even  if  this  bacillus  were  proved 
to  be  peculiar  to  leprosy,  in  the  absence  of  suc- 
cessful inoculations  with  pure  cultures  its  causal 
relation  to  the  disease  must  remain  in  question; 
for,  in  view  of  what  we  know  of  the  habits  of  the 
bacteria  generally,  there  is  nothing  improbable 
in  the  supposition  that  this  particular  species  is 
able  to  invade  tissues  of  a  low  grade  of  vitality, 
and  finds  in  the  leprous  tubercles  the  pabulum 
necessary  for  its  development.  If,  however,  lep- 
rosy is  truly  an  infectious  disease,  which  seems  to 
be  a  matter  of  considerable  doubt,  the  rapidly 
accumulating  evidence  in  favor  of  the  parasitic- 
germ  theory,  in  explanation  of  the  etiology  of 
these  diseases,  lends  strong  probability  to  the 
first-mentioned  hypothesis. 

Hansen  has  endeavored  to  inoculate  rabbits  with 
leprosy,  by  introducing  portions  of  the  leprous 


336  BACTERIA  IN  INFECTIOUS  DISEASES. 

growths,  especially  the  tubercles,  under  the  skin 
of  these  animals.  He  says,  "  I  was  not  lucky  in 
any  of  these  attempts."  (1880.)  More  recently 
he  has  inoculated  a  monkey,  which,  at  the  date 
of  his  report,  had  been  under  observation  for  six 
months,  without  having  developed  any  symptoms 
of  the  disease.  But  as  the  time  of  incubation  in 
man  is  said  to  be  a  year  or  more,  this  experiment 
is  not  considered  decisive. 

The  bacilli  have  been  successfully  cultivated  by 
their  discoverer  upon  gelatinized  blood-serum.  In 
these  cultures  development  commenced  after  an 
interval  of  three  or  four  days,  and  the  bacilli 
often  presented  nodular  enlargements  at  the  ex- 
tremities, which  were  believed  to  be  due  to  the 
formation  of  spores.  In  these  cultures  filaments 
formed,  made  up  of  a  number  of  bacilli,  and  these 
were  often  so  abundant  as  to  form  an  entangled 
net-work.  The  fact  that  these  bacilli  multiply  and 
develop  spores  in  a  culture-solution,  within  a  few 
days,  while  the  period  of  incubation  in  leprosy  is 
"at  least  a  year,"  seems  a  little  difficult  to  recon- 
cile with  the  supposed  etiological  role  of  these 
parasites. 

MALIGNANT  (EDEMA.  —  According  to  Koch,  a 
frequent  source  of  error  in  experiments  on  anthrax 
arises  from  accidental  contamination  of  the  culture- 
fluids  by  a  bacillus  which  closely  resembles  B.  an- 
thracix.  This  organism  is  called  the  bsx'illns  of 
malignant  oedema,  and  the  disease  to  which  it  gives 


MALIGNANT   (EDEMA.  337 

rise  has  been  especially  studied  by  Gaffky,  who 
states  that  the  organism  is  apparently  identical 
with  the  vibrion  septique  of  Pasteur. 

Although  very  similar  to  the  anthrax  bacillus, 
Koch  points  out  certain  morphological  characters 
which  distinguish  the  one  from  the  other.  The 
anthrax  bacilli  are  a  little  broader  than  the  others, 
and  the  joints  have  concave  extremities ;  whereas 
the  others  are  rounded  at  the  extremity.  B.  an- 
thracis  is  motionless,  while  that  of  malignant  oedema 
is  usually  in  active  motion.  According  to  Ewart, 
the  anthrax  bacillus,  also,  is  motile  during  certain 
stages  in  its  life-history  :  — 

"  The  disease  is  readily  produced  by  the  introduction 
of  a  small  quantity  of  garden-earth  under  the  skin  of  an 
animal  (rabbit,  guinea-pig,  or  mouse).  The  animals 
become  ill  very  soon,  there  being  no  distinct  incubation 
period,  and  death  occurs  after  twenty-four  to  forty-eight 
hours.  Spreading  from  the  point  of  infection,  the  sub- 
cutaneous cellular  tissue  and  the  intermuscular  cellular 
tissue  become  oedematous  and  reddened,  the  spleen  is 
enlarged,  soft,  and  of  a  dark  reddish-blue  color  ;  but  the 
other  organs  are  not  altered  to  the  naked  eye.  No 
bacilli,  or  only  very  few,  are  found  in  the  blood  of  the 
heart  immediately  after  death ;  but  the  fluid  obtained 
after  section  of  the  various  organs  contains,  numbers  of 
these  moving  rods.  The  longer  the  time  which  has 
elapsed  after  death,  the  more  numerous  do  the  bacilli 
in  the  tissues  and  blood  become.  They  grow  best  in  the 
dead  body,  thus  differing  from  other  pathogenic  organ- 
isms. On  section  of  the  organs,  the  bacilli  are  found  in 
the  cellular  tissue,  almost  exclusively  towards  the  sur- 

22 


338  BACTERIA  IN  INFECTIOUS   DISEASES. 

face ;  they  apparently  spread  into  the  organs  from  the 
cellular  tissue  around.  They  may  also  form  plugs  in 
the  capillaries,  though  this  is  rare.  In  some  cases 
putrefaction  occurs  rapidly,  but  in  others  it  is  apparently 
retarded. 

"  With  regard  to  the  cultivation  of  these  organisms 
outside  the  body,  it  has  been  found  by  Pasteur,  Joubert, 
etc.,  that  they  will  not  develop  in  presence  of  oxygen, 
but  readily  grow  when  carbonic-acid  gas  is  substituted 
for  oxygen  in  the  cultivating  flasks.  This  observation  is 
confirmed  by  Gaffky,  who  grew  them  in  the  interior  of 
potatoes  removed  from  the  air.  These  bacilli  caused 
death  when  injected  into  the  subcutaneous  cellular 
tissue,  thus  showing  that  they  were  the  true  materies 
morbi. 

"  Of  great  interest  is  the  question  of  the  relation  of 
these  organisms  to  those  found  by  Lewis  in  the  blood 
of  asphyxiated  animals,  especially  of  rats,  —  an  observa- 
tion confirmed  by  Gaffky.  These  organisms  are  found 
most  frequently  in  the  blood  of  horses,  and  Koch  ex- 
plains this  by  the  slower  cooling  of  their  bodies.  In 
smaller  animals,  these  organisms,  which  probably  come 
from  the  intestine,  do  not  develop  rapidly,  unless  the 
body  be  kept  at  a  temperature  of  about  38°  C.  Dr. 
Gaffky  asphyxiated  a  guinea-pig,  and  then  placed 
the  body  in  an  incubator.  In  twenty-four  hours  the 
body  was  much  swollen  from  gas-development ;  and  from 
the  natural  orifices  bloody  fluid  exuded,  containing 
numerous  bacilli  indistinguishable  from  oedema  bacilli. 
Everywhere  throughout  the  body,  more  especially  in 
the  subcutaneous  cellular  tissue,  these  bacilli  were 
present  in  large  numbers.  A  drop  of  fluid  from  the 
cellular  tissue  was  injected  into  a  second  guinea-pig. 
This  animal  died  on  the  following  day,  wfth  the  typical 
appearances  of  malignant  oedema.  A  minute  quantity 


MILK   SICKNESS.  339 

of  the  cedematous  fluid,  dilated  with  distilled  water, 
and  injected  into  a  third  guinea-pig,  was  followed  by 
the  same  result."1 

MILK  SICKNESS.  —  This  is  an  infectious  disease 
which  prevails  in  certain  rural  districts  in  the 
United  States,  and  which  is  said  gradually  to 
recede  before  the  advance  of  improved  agricul- 
ture :  — 

"  In  its  source,  in  unimproved  marshy  localities,  it 
closely  resembles  the  malignant  anthrax  ;  also,  in  its 
communicability  to  all  animals ;  but  it  differs  essen- 
tially in  that  it  fails  to  show  local  anthrax  lesions,  in 
place  of  which  it  expends  its  energy  on  the  nerve 
centres,  producing  great  hebetude  and  loss  of  muscular 
power.  According  to  Dr.  Phillips  it  is  characterized 
by  the  presence  in  the  blood  of  a  microzyme  (spirillum) 
like  that  seen  in  relapsing  fever.  The  germ  is  probably 
derived  from  drinking-water,  or  the  surfaces  of  veg- 
etables, as  certain  wells  are  found  to  infect  with  cer- 
tainty, and  the  disease  has  been  repeatedly  produced 
by  feeding  upon  particular  plants  (Rhus  toxicodendron, 
etc.).  That  these  plants,  in  themselves,  are  not  the 
pathogenic  elements,  is  shown  by  their  innocuous  prop- 
erties when  grown  in  places  out  of  the  region  of  the 
milk-sickness  infection.  It  seems  altogether  probable 
that  here,  as  in  malignant  anthrax,  we  are  dealing  with 
a  microzyme  which  has  developed  pathogenic  properties, 
and  which  can  be  reproduced  indefinitely  in  the  bodies 
of  living  animals.  The  great  danger  of  this  affection 
consists  in  the  conveyance  of  the  germ  with  unimpaired 
potency  through  the  flesh  and  milk,  and  through  man- 
ufactured products  of  the  latter,  —  butter  and  cheese. 

1  Quoted  from  The  British  Medical  Journal,  July  15, 1882,  p.  99. 


340  BACTERIA  IN  INFECTIOUS  DISEASES. 

Some  even  hold  that  in  animals  giving  milk  the  s}rstem 
does  not  suffer  material!}',  but  that  it  is  saved  by  the 
drainage  of  the  germs  through  the  mammary  glands, 
and  that  thus  a  milk-sick  cow  may  remain  for  a  con- 
siderable time  unsuspected.  .  .  .  The  disorder  proves 
fatal  in  man  as  in  animals."  1 

A  careful  study  of  this  disease  by  the  experi- 
mental method  would  probably  demonstrate  its 
parasitic  nature  ;  and  it  is  extremely  desirable  that 
its  etiology  may  be  worked  out,  both  in  the  inter- 
est of  science  and  of  medicine. 

MEASLES.  —  Coze  and  Feltz  state  that  bacteria 
are  found  in  the  blood  of  measles,  of  extreme 
minuteness  and  great  mobility.  In  the  period  of 
invasion  the  nasal  mucus  contains  small  "bacteri- 
form  elements."  The  inoculation  of  this  blood  did 
not  produce  the  death  of  rabbits ;  but  these  animals 
were  sick  for  two  or  three  days,  as  the  result  of 
such  inoculations,  and  "  very  slender  and  active 
rods"  were  found  in  their  blood  (Magnin).  Klebs, 
also,  found  micrococci  in  the  trachea,  and  in  blood 
taken  from  the  heart  of  infants  that  had  fallen 
victims  to  this  disease.  In  the  blood,  preserved  in 
capillary  tubes,  these  micrococci  developed  in 
spherical  masses. 

Braidwood  ai\d  Vacher  describe  certain  small 
spherical  bodies  first  found  by  them  in  the  breath 
of  children  in  the  acute  stage  of  the  disease,  which 
they  believe  to  be  the  contagious  elements.  These 

1  Prof.  James  Law,  National  Board  of  Health  Bulletin,  Vol.  II.  No. 
4,  p.  466. 


PLEURO-PNEUMONIA.  341 

are  "  sparkling,  colorless  bodies,  something  like 
those  found  in  vaccine,  but  larger."  Some  were 
spherical,  others  were  elongated,  with  sharpened 
ends.  The  breath  of  healthy  children  did  not 
contain  these  sparkling  bodies.  These  bodies 
were  also  found  in  the  lungs  and  liver  of  two 
children  who  died  of  measles. 

Keating  has  recently  (1882)  reported  the  find- 
ing of  micrococci  in  the  blood  of  malignant 
measles,  and  their  absence  in  cases  of  mild  type. 
He  says  :  "  The  micrococcus  is  found  in  the  con- 
tents of  pustules  and  vesicles,  and  also  in  the 
blood  taken  from  the  measles-papule  in  mild 
cases,  without  its  being  present  in  the  blood  taken 
from  the  punctured  finger.  In  severe  cases,  called 
malignant  in  this  paper,  owing  to  the  rapid  ap- 
pearance of  morbid  symptoms,  the  blood  shows, 
early  in  the  attack,  numerous  patches  of  micro- 
coccus  in  the  field."  These  observations  were 
verified  by  Formad. 

PLEURO-PNEUMONIA.  —  The  infectious  disease 
of  cattle  known  as  pleuro-pneumonia  has  been 
studied  experimentally  by  Willems,  Banti,  Bouley, 
Leblanc,  Bruylants,  Verriest,  and  others,  and 
strong  evidence  has  been  adduced  in  favor  of  the 
view  that  it  is  due  to  a  parasitic  micro-organism. 
In  1852  Willems  pointed  out  the  existence  of 
certain  peculiar  corpuscles  in  the  lymph  obtained 
by  incision  of  the  lung  of  an  animal  dead  from 
this  disease.  This  observation  has  been  confirmed 


342  BACTERIA  IN  INFECTIOUS  DISEASES. 

by  others,  and  Brnylants  and  Verriest  describe  tbe 
organism,  which  they  were  able  to  cultivate  in 
sterilized  fluids,  as  a  micrococcus,  sometimes  isola- 
ted, sometimes  in  pairs,  and  sometimes  in  chains 
of  3-10  elements.  The  form  is  slightly  oval,  and 
the  size  varies  considerably,  the  largest  measuring 
1  p.  in  diameter. 

Protective  inoculations  are  successfully  practised 
in  this  disease. 

INFECTIOUS  PNEUMONIA.  —  That  there  is  an  in- 
fectious form  of  pneumonia  in  man  is  now  pretty 
generally  admitted  upon  clinical  evidence  ;  and 
several  observers  have  described  micro-organisms 
supposed  to  bear  a  causal  relation  to  this  disease. 
Klebs  claims  to  have  produced  lobular  pneumonia 
in  rabbits  by  injecting  the  sputum  of  patients  suf- 
fering from  pneumonia,  in  which  he  found  an  or- 
ganism called  by  him  monas  pulmonale.  Friedlander, 
also,  found  micro-organisms  in  eight  successive 
cases  in  the  expectoration  and  in  sections  of  pul- 
monary tissue.  These  micrococci  were  elliptical 
in  shape,  one  micro-millimetre  in  length,  and 
two-thirds  p,  in  breadth.  They  were  usually  in 
pairs,  but  also  occurred  in  chains,  and  were  found 
most  abundantly  in  the  fibrinous  expectoration, 
and  in  grayish-red  hepatization. 

The  writer  would  call  attention  to  the  fact  that 
these  oval  micrococci  seem  to  resemble  closely  those 
found  in  the  blood  of  a  rabbit  killed  by  the  subcuta- 
neous injection  of  human  saliva.  (See  Fig.  3,  Plate 


PYJEMIA  IN  RABBITS.  343 

VI.,  and  also  p.  359.)  Leyden  has  demonstrated  the 
presence  of  numerous  micrococci  corresponding 
with  those  described  by  Friedlander  in  exudation 
fluid  obtained  during  life  from  a  patient  suffering 
from  severe  croupous  pneumonia.  The  fluid  was 
withdrawn  by  means  of  a  hypodermic  syringe. 
Giinther.  also,  has  obtained  the  same  result  from 
an  exploratory  puncture  of  hepatized  lung.  On 
the  other  hand,  negative  results  were  obtained  by 
Leyden  in  two  milder  cases  of  pneumonia  in  which 
fluid  was  withdrawn  from  the  inflamed  lung;  and 
in  an  epidemic  described  by  Kiihn,  search  for 
micro-organisms  gave  a  negative  result. 

PYAEMIA  IN  RABBITS,  Koch.  —  After  failing  to 
produce  a  general  infection  in  rabbits  by  the 
injection  of  putrid  blood,  Koch  succeeded  with  a 
fluid  obtained  by  macerating  for  two  days  in  dis- 
tilled water  a  bit  of  the  skin  of  a  mouse.  The 
animal  died  at  the  end  of  one  hundred  and  five 
hours,  and  a  purulent  infiltration  of  the  subcuta- 
neous cellular  tissue  was  found,  extending  from 
the  point  of  inoculation  as  far  as  the  hip  behind, 
and  to  the  middle  of  the  belly  below.  The  peri- 
toneal cavity  contained  a  turbid  fluid,  and  its 
walls  were  covered  in  places  by  white  patches. 
The  liver  was  covered  with  a  fibrinous  exudation, 
and  presented  a  grayish  mottled  appearance  ;  upon 
section  it  showed  gray,  wedge-shaped  patches.  In 
the  lungs  were  found  dark  red  patches,  the  size  of 
a  pea. 


344  BACTERIA  IN  INFECTIOUS  DISEASES. 

A  syringeful  of  blood  from  thte  animal  killed  a 
second  rabbit  in  forty  hours.  Rabbit  No.  3  was 
killed  in  fifty-four  hours  by  three  drops  of  blood 
from  No.  2 ;  one  drop  from  No.  3  killed  No.  4  in 
ninety-two  hours;  one-tenth  of  a  drop  from  No. 
4  killed  No.  5  in  one  hundred  and  twenty-five 
hours.  The  pathological  appearances  in  this  se- 
ries of  rabbits  were  similar  to  those  noted  in 
the  first,  viz. :  — 

"  Local  purulent  cedematous  infiltration  of  the  sub- 
cutaneous cellular  tissue ;  metastatic  deposits  in  the 
lungs  and  liver ;  swelling  of  the  spleen  and  peritonitis. 
These  appearances  harmonize  so  closely  with  those 
commonly  designated  as  pyaemia  that  I  do  not  hesitate 
to  use  that  term  for  the  disease  under  consideration. 

"  On  microscopic  examination  micrococci  are  found 
in  great  numbers  everywhere  throughout  the  body,  and 
more  especially  in  parts  which  have  undergone  altera- 
tions visible  to  the  naked  eye.  These  micrococci  are, 
for  the  most  part,  single  or  in  pairs,  and  their  meas- 
urement is  therefore  difficult.  Ten  measurements  of 
pairs  of  micrococci  differed  but  little  from  each  other, 
and  gave  .25  /JL.  as  the  average  diameter  of  a  single 
individual." 

It  will  be  noticed  that  this  is  much  less  than  the 
size  of  the  oval  micrococcus  which  produces  septi- 
caemia in  rabbits. 

"As  regards  size,  therefore,  they  stand  midway 
between  the  chain-like  micrococcus  of  the  progressive 
gangrene  of  the  tissues  and  the  zoogloea-forming  micro- 
coccus  of  the  cheesy  abscesses  of  rabbits.  Their  relation 
to  the  blood-vessels  can  be  best  seen  in  the  renal  capil- 


PYAEMIA  IN  RABBITS. 


345 


Fig.  18. 


laries,  and  I  have 
therefore  selected  a 
small  vessel  from  the 
cortex  of  the  kidney 
for  delineation  (Fig. 
18) 

"  In  the  interior  of 
the  vessel,  at  c,  is  a 
dense  deposit  of  mi- 
crococci  adherent  to 
the  wall,  and  enclos- 
ing in  its  substance 
a  number  of  red  blood- 
corpuscles.  This  mass 
would  probably  have  very  soon  filled  the  calibre  of  the 
vessel ;  for  fresh  corpuscles  are  constantly  being  de- 
posited upon  it,  and  these  become  surrounded  by  deli- 
cate offshoots  from  the  mass  of  micrococci.  From  this 
we  may  conclude,  either  that  the  micrococci  have  of 
themselves,  owing  to  the  nature  of  their  surface,  the 
power  of  causing  the  red  blood-corpuscles,  to  which 
they  adhere,  to  stick  together,  or  that  these  organisms 
can  occasion  coagulation  of  the  blood  in  their  vicinity, 
and  thus  the  formation  of  thrombi.  .  .  . 

"  Such  partial  or  complete  thrombus  formations  oc- 
cur in  the  renal  vessels  in  many  places,  particularly  in 
the  glomeruli,  where  individual  capillary  loops  may 
be  found  completely  blocked  by  micrococci.  ...  In  the 
larger  vessels,  also,  groups  of  considerable  size  are 
formed,  and  I  am  disposed  to  believe  that  the  large 
metastatic  deposits  in  the  liver  and  in  the  lungs  do  not 
arise  by  gradual  growth  of  a  mass  of  micrococci,  but  by 
the  arrest  of  large  groups  of  micrococci  and  of  clots 
associated  with  them,  formed  in  the  manner  described, 


346  BACTERIA  IN  INFECTIOUS   DISEASES. 

iii  the  circulating  blood ;  in  other  words,  by  true  em- 
bolism." * 

RELAPSING  FEVER.  —  The  presence  in  the  blood 
of  patients  suffering  from  relapsing  fever  of  a 
parasitic  micro-organism,  of  spiral  form,  and  ex- 
hibiting active  movements,  was  discovered  by 
Obermeier  in  1868.  Since  this  date  numerous  ob- 
servers have  confirmed  the  discovery,  and  have 
verified  the  fact  that  this  parasite  is  uniformly 
found  in  the  blood,  in  this  disease,  when  the  fever 
is  at  its  acme,  both  during  the  first  invasion  and 
the  relapse.  It  disappears  very  quickly,  how- 
ever, when  defervescence  occurs.  These  spiral 
filaments  (see  Fig.  3,  Plate  VII.)  are  extremely 
slender,  the  diameter  never  exceeding  1  p..  Their 
length  is  from  150  to  200  p.. 

"  Their  motion  is  very  lively,  rotatory,  twisting,  and 
rapidly  progressive;  but  soon  ceases  under  the  ordinary 
conditions  of  microscopic  examination.  As  the  blood 
under  examination  cools  and  begins  to  coagulate,  these 
movements  become  slower,  and  many  spiral  filaments 
become  covered  with  very  fine  threads  of  fibrine " 
(Lebert). 

Inoculation  of  monkeys  with  the  blood  of  re- 
lapsing fever-patients  has  been  successfully  prac- 
tised by  Koch  and  by  Carter.  Both  of  these 
experimenters  have  also  succeeded  in  cultivating 
the  spirochaete  external  to  the  living  body. 

1  Traumatic  Infective  Diseases,  Sydenham  Society's  translation,  p.  61. 


RELAPSING  FEVER.  347 

As  the  result  of  numerous  experiments  upon 
monkeys,  Carter  arrives  at  the  following  con- 
clusions :  — 

"1.  The  spirillum  fever  (relapsing  fever)  of  man  is 
directly  transmissible  to  a  quadrumanous  animal.  2. 
There  occurs  a  non-febrile  infection  of  the  blood  prior 
to  4  fever.'  3.  Though  the  blood-spirillum  was  never 
seen  in  the  monkey  without  fever  ensuing  sooner  or 
later,  yet  the  p^yrexia  is  secondary  in  time,  and  is  sus- 
ceptible of  highly  varied  manifestations  ;  and  the  spir- 
illum-disease might  be  denned  as  essentially  a  mycosis 
sanguinis  cum  febre." 

MotschutkofFsky  has  performed  inoculation  ex- 
periments upon  man,  and  was  successful  with  blood 
taken  during  the  pyrexia;  while  apyretic  blood, 
milk,  urine,  etc.,  gave  negative  results.  Accord- 
ing to  Heidenreich,  "  The  addition  of  equal  parts 
of  water  to  the  blood  is  fatal  to  the  spirochaete. 
Its  activity  is  not  affected  by  any  internal  admin- 
istration of  quinine,  salicylate  of  soda,  or  other 
agents,  and  externally  only  affected  by  about  one 
per  cent  of  quinine."  l 

The  evidence  in  favor  of  the  essential  etiological 
relation  of  Spirochcete  Obermeieri  to  the  form  of 
fever  with  which  it  is  associated  is  very  strong, 
independently  of  the  confirmatory  experimental 
evidence. 

We  have  here  a  peculiar  parasite  invading  the 
blood  in  very  great  numbers  during  the  access  of 

1  Quoted  from  Shattuck,  in  Supplement  to  Ziernssen's  Cyclopaedia. 


348  BACTERIA  IN  INFECTIOUS  DISEASES. 

the  fever;  the  uniform  presence  of  which,  during 
the  first  invasion  and  the  relapses,  has  been  verified 
by  numerous  observers  in  various  parts  of  the 
world.  Inasmuch  as  the  blood  of  healthy  persons 
is  free  from  bacterial  organisms  of  any  kind,  and 
as  this  peculiar  organism  is  not  found  in  any  other 
febrile  affection,  the  presumption  is  altogether  in 
favor  of  its  causal  relation.  Looking  at  it  from 
another  point  of  view,  it  is  difficult  to  believe  that 
the  vital  fluid  could  be  invaded  by  myriads  of 
active  parasitic  organisms,  which  must  appropriate 
to  their  own  use  material  required  to  preserve  the 
integrity  of  the  circulating  fluid  and  for  the  nu- 
trition of  the  tissues,  without  some  disturbance 
of  the  economy  resulting.  In  other  words,  we  can 
easily  understand  that  the  presence  of  the  spiro- 
chsete  might  give  rise  to  the  fever  and  other  phe- 
nomena of  the  disease ;  but  there  is  nothing  in 
our  experience  to  indicate  that  fever  causes  the 
appearance  in  the  blood  of  parasitic  organisms  of 
this  description. 

The  evidence  in  this  case  is  very  different  from 
that  relating  to  the  presence  of  micro-organisms 
in  morbid  products  of  a  low  grade  of  vitality  found 
during  life,  or  the  demonstration  post  mortem  of 
similar  organisms  in  the  blood  or  tissues.  And 
while  we  may  demand,  as  final  proof,  that  the  dis- 
ease shall  be  produced  by  inoculation  with  a  "  pure 
culture"  of  the  parasite,  yet,  in  the  absence  of 
such  demonstration,  it  must  be  admitted  that  the 
evidence  is  very  convincing  as  to  the  causal  re- 


SCARLET  FEVER.  349 

lation  of  Spirochcete    Obermeieri  to  the  disease  in 
question. 

SCARLET  FEVER.  —  "  Coze  and  Feltz  have  found 
in  the  blood  of  scarlet  fever,  taken  from  patients, 
living  or  recently  dead,  some  rods  as  well  as  mo- 
bile points.  This  blood  injected  into  the  cellular 
tissue  of  rabbits  has  sometimes  produced  death, 
and  the  blood  of  the  animals  experimented  upon 
has  presented  the  same  bacteria  as  human  blood 
of  scarlatina :  they  are  simply  a  little  larger  and 
longer.  As  to  the  mobile  points,  they  appear  to 
correspond  to  the  micrococcus  of  scarlatina  de- 
scribed by  Hallier"  (Magnin).  Reiss  found,  in 
blood  drawn  from  a  vein  in  the  arm  of  a  patient 
dying  of  scarlet  fever,  that  "  the  serum  was  filled 
with  an  infinite  number  of  small,  rapidly  oscillating 
bodies,  which,  under  a  magnifying  power  of  five 
hundred  diameters,  appeared  as  black  points  be- 
tween the  groups  of  blood  corpuscles.  In  addition, 
there  were  also  rod-like  formations,  which  at  many 
places  were  recognized  as  being  composed  of  three 
or  four  or  more  of  these  minute  bodies  disposed  in 
rows."  Reiss  injected  a  few  drops  of  this  blood 
under  the  skin  of  the  back  of  a  rabbit,  with  the 
effect  of  developing  like  small  bodies  in  its  blood, 
and  causing  death  in  twenty-four  hours.  Further 
inoculations  with  this  rabbit's  blood  gave  rise  to 
identical  results.1  In  the  experiments  of  Coze 
and  Feltz,  the  introduction  of  a  small  quantity  of 

1  Thomas  in  Ziemssen's  Cyclopaedia. 


350  BACTERIA  IN  INFECTIOUS  DISEASES. 

scarlatinous  blood  beneath  the  skin  of  rabbits 
proved  fatal  to  sixty-two  out  of  sixty-six  animals 
experimented  upon.  (Query:  Was  this  blood 
obtained  post  mortem,  or  during  the  life  of  the 
patients  ?) 

The  evidence  that  the  rabbits,  in  the  experi- 
ments referred  to,  suffered  a  genuine  attack  of 
scarlet  fever,  is  not  satisfactory ;  and  it  must  be 
remembered,  in  estimating  the  scientific  value  of 
such  experiments,  that  rabbits  are  very  subject  to 
infectious  forms  of  septicaemia ;  and  that  the  blood 
of  man  and  animals,  obtained  post  mortem  from  a 
variety  of  acute  febrile  diseases,  will  produce  sim- 
ilar results.  On  the  other  hand,  it  must  be  ad- 
mitted that,  in  its  short  period  of  incubation  and 
in  other  particulars,  malignant  scarlet  fever  resem- 
bles the  infectious  forms  of  septicaemia  in  the 
lower  animals,  shortly  to  be  described  ;  and  that 
septicaemia  in  man  is  sometimes  attended  with  a 
scarlet  eruption  resembling  exactly  that  which 
characterizes  the  disease  under  consideration. 

The  occurrence  of  disease,  supposed  to  be  iden- 
tical with  scarlet  fever  in  man,  among  the  domes- 
tic animals,  —  horses,  dogs,  cats,  swine,  —  has  been 
noted  by  several  observers  ;  and  in  certain  cases 
communication  of  the  disease  by  contagion  has 
been  traced.  "  Thus  Heim  observed  that  a  dog 
which  had  lain  in  the  same  bed  with  a  scarlatinous 
child,  was  taken  with  fever;  followed  by  scarla- 
tina and  desquamation."  l 

1  Thomas  in  Ziemasen's  Cyclopaedia. 


SEPTICAEMIA  IN  MICE.  351 

The  resources  of  modern  science  have  not  yet 
been  fairly  brought  to  bear  for  the  elucidation  of 
the  etiology  of  this  pestilential  disease,  which  in 
all  countries  contributes  so  large  a  share  to  the 
mortality  among  young  children;  and  it  is  to  be 
hoped  that  some  government,  more  liberal  in  this 
direction  than  is  that  of  the  United  States,  may 
undertake  a  thorough  experimental  investigation, 
in  the  interests  of  its  citizens,  if  the  advancement 
of  science  per  se  is  not  a  sufficient  motive.  The 
unsatisfactory  results  heretofore  attained  are  doubt- 
less to  be  ascribed  to  the  fact  that  the  difficulties 
connected  with  the  solution  of  the  problem  are 
too  great  to  be  met  by  individual  enterprise,  and 
also  to  the  fact  that  no  amount  of  enthusiasm  can 
take  the  place  of  skill  and  experience  in  investiga- 
tions of  this  nature.  Enough  has  been  done  to 
show  that  the  persistent  efforts  of  trained  experts, 
supported  by  liberal  government  patronage,  will 
be  required  for  the  settlement  of  the  more  difficult 
problems  in  etiology. 

SEPTICAEMIA  IN  MICE,  Koch.  —  Koch  at  first 
failed  to  produce  an  infectious  disease  in  mice  by 
the  subcutaneous  injection  of  putrid  fluids,  —  blood, 
meat  infusion,  etc.,  —  although  the  injection  of  a 
sufficient  quantity  of  these  fluids  produced  death 
in  a  few  hours.  Thus  five  drops  of  putrid  blood 
caused  the  death  of  a  mouse  in  four  to  eight  hours, 
and  the  symptoms  of  poisoning  were  developed 
immediately.  But  no  bacteria  were  found  in  blood 


352  BACTERIA  IN  INFECTIOUS   DISEASES. 

taken  from  the  heart,  or  in  the  internal  organs  of 
a  mouse  killed  by  such  an  injection  ;  nor  did  its 
blood,  taken  from  the  right  auricle,  cause  the  death 
of  other  mice  into  which  it  was  injected.  The 
symptoms  of  poisoning  in  these  cases  were  more 
or  less  severe  according  to  the  amount  of  septic 
material  introduced,  and  no  doubt  were  due  to  the 
chemical  poison,  sepsin,  which  is  present  in  putrid 
blood.  But  when  small  quantities  of  this  putrid 
blood  were  injected,  it  happened  that,  while  a 
majority  of  the  little  animals  experienced  no  per- 
ceptible effects  from  the  injection,  a  certain  num- 
ber fell  ill  at  the  end  of  twenty-four  hours,  and 
death  occurred  in  forty  to  sixty  hours  from  the 
time  of  inoculation.- 

In  these  cases  the  symptoms  and  post  mortem 
appearances  were  of  a  definite  character,  and  the 
disease  was  proved  to  be  infectious.  This  was 
shown  by  inoculation  from  mouse  to  mouse  of  a 
minute  quantity  of  blood,  —  one-tenth  of  a  drop 
was  ample.  Koch  says :  "  I  have  performed  these 
experiments  on  fifty-four  mice,  and  have  always 
obtained  the  same  result.  Of  these,  seventeen 
inoculations  were  made  in  succession."  1  We  must 
refer  the  reader  to  Koch's  work  for  the  symp- 
toms and  pathological  appearances  which  charac- 
terize this  infectious  disease ;  its  etiology  alone 
concerns  us  here. 

The  certainty  with  which  the  infective  material 
can  be  carried  from  one  animal  to  another  is  said 

1  Traumatic  Infective  Diseases. 


SEPTIC^MIA  IN  MICE. 


353 


to  be  even  greater  than  in  anthrax.  In  order  to 
infallibly  bring  about  the  death  of  one  of  these 
little  animals  within  the  time  stated,  —  about  fifty 
hours,  —  it  is  sufficient  to  pass  the  point  of  a 
scalpel,  which  has  been  in  contact  with  the  in- 
fected blood,  over  a  small  wound  in  the  skin. 

Koch  suspected  that  this  great  virulence  was 
due  to  the  abundant  presence  of  a  micro-organism 
in  the  infectious  material, 
but  failed  in  his  earlier  ef- 
forts to  find  this  parasite  in 
septiccemic  blood.  This  was 
found,  later,  to  be  owing  to 
the  minute  size  of  the  ba- 
cilli to  which  the  disease  is 
ascribed ;  and  by  the  use  of 
Abbe's  condenser  he  was 
able  to  demonstrate  the 
presence  in  large  numbers 
of  the  bacilli  seen  in  Fig.  19, 
which  is  copied  from  his  work  (I.  c.). 

"The  bacilli  lie  singly  or  in  small  groups  between  the 
red  blood  corpuscles,  and  have  a  length  of  .8  to  1  p. 
Their  thickness,  which  cannot  be  measured  accurately, 
but  only  approximately  estimated,  is  about  .1  to  .2  //,. 
.  .  .  One  often  sees  the  bacilli  in  septiesemic  blood 
attached  to  each  other  in  pairs,  either  in  straight  lines 
or  forming  an  obtuse  angle.  Chains  of  three  or  four 
bacilli  also  occur,  but  they  are  rare.  .  .  .  Without  the 
use  of  staining  materials,  the  bacilli  can  only  with 
extreme  difficulty  be  recognized  in  fresh  blood,  even 
when  one  is  familiar  with  their  form ;  and  I  have  not 

23 


Fig.    19. 

White  blood-corpuscles  from  one 
of  the  veins  of  the  diaphragm  of 
a  septicaemic  mouse.  X  700. 


354  BACTERIA  IN  INFECTIOUS  DISEASES. 

been  able  to  obtain  any  certain  evidence  as  to  whether 
they  move  or  not.  Their  relation  to  the  white  blood 
corpuscles  is  peculiar.  They  penetrate  these,  and  mul- 
tiply in  their  interior.  One  often  finds  that  there  is 
hardly  a  single  white  corpuscle  in  the  interior  of  which 
bacilli  cannot  be  seen.  Many  corpuscles  contain  isolated 
bacilli  only ;  others  have  thick  masses  in  their  interior, 
the  nucleus  being  still  recognizable ;  while  in  others  the 
nucleus  can  be  no  longer  distinguished ;  and  finally 
the  corpuscle  may  become  a  cluster  of  bacilli,  breaking 
up  at  the  margin,  —  the  origin  of  which  one  could  not 
have  explained  had  there  been  no  opportunity  of  seeing 
all  the  intermediate  steps  between  the  intact  white 
corpuscle  and  these  masses  (Fig.  19).  Starting  from 
the  point  of  inoculation,  one  can  easily  see  the  path  by 
which  the  bacilli  have  penetrated  into  the  body.  In  the 
subcutaneous  cellular  tissue  in  the  neighborhood  of  the 
inoculated  spot  they  are  very  numerous,  and  at  times 
accumulated  in  dense  masses,  as  can  be  best  observed 
in  inoculations  on  the  ear.  ...  I  have  never  found 
these  bacilli  in  the  lymphatic  vessels.  ...  I  have  not 
found  them  free  in  the  cavities  of  the  body.  ...  In 
the  capillaries  the  bacilli  congregate,  particularly  at  the 
points  of  division ;  but  I  have  never  yet  seen  a  complete 
obstruction  of  the  smaller  vessels  produced  in  this  way. 
...  In  exactly  the  same  manner  are  the  bacilli  dis- 
tributed in  the  rest  of  the  vascular  system.  In  the  ex- 
amination of  sections  of  lung,  liver,  kidney,  and  spleen, 
one  meets  everywhere  with  vessels  containing  free 
bacilli,  and  with  white  blood  corpuscles  with  bacilli  in 
their  interior.  .  .  .  The  whole  morbid  process  has  thus 
a  great  resemblance  to  anthrax.  In  both  diseases  the 
infective  power  of  the  blood  is  due  to  the  bacilli  present 
in  it ;  as  soon  as  these  disappear,  the  disease  can  be  no 
longer  produced  by  inoculation  with  the  blood.  Both 


SEPTICAEMIA  IN  RABBITS.  355 

diseases  are  distinguished  by  the  invariable  develop- 
ment of  exceedingly  numerous  bacilli.  There  can  thus 
be  no  doubt  that  the  bacilli  of  the  septicsemia  described 
here  possess  the  same  significance  as  the  bacilli  of 
splenic  fever,  namely,  that  they  are  to  be  regarded  as 
the  contagium  of  this  disease." 

Very  interesting  are  the  results  obtained  by 
Kocb  in  his  attempts  to  infect  other  animals  with 
the  blood  of  septicsemic  mice.  The  rabbit,  so  sus- 
ceptible to  anthrax  and  to  other  forms  of  septicae- 
mia, resisted  not  only  inoculations  with  small 
amounts  of  the  virulent  blood,  but  the  entire 
amount  of  blood  from  a  septicsemic  mouse  failed  to 
produce  any  effect.  Field  mice,  also,  although  so 
closely  resembling  house  mice,  upon  which  the 
successful  experiments  were  made,  proved  not  to 
be  susceptible  to  the  disease. 

SEPTICAEMIA  IN  RABBITS.  —  The  writer  discov- 
ered accidentally,  in  September,  1880,  the  virulent 
properties  of  his  own  saliva  when  injected  into 
rabbits,  and  has  since  demonstrated  the  fact  that 
the  highly  infectious  disease  which  results  from 
such  an  inoculation  is  due  to  a  micrococcus  con- 
stantly present  in  the  buccal  secretions,  —  i.  e.,  in 
the  mixed  secretions  as  found  in  the  mouth. 
The  experiment  which  led  to  this  discovery  was 
made  as  a  check  upon  other  inoculation  experi- 
ments, with  a  view  to  ascertain  whether  a  fluid 
supposed  to  be  innocuous  would  produce  any  no- 
ticeable febrile  disturbance  when  injected  beneath 


356  BACTERIA  IN   INFECTIOUS  DISEASES. 

the  skin  of  a  rabbit.  The  unexpected  death  of  the 
animal  led  to  a  repetition  of  the  experiment,  with 
the  same  result,  except  when  the  animal  experimented 
upon  had  previously  been  inoculated  with  various  fluids 
containing  bacteria.  These  exceptions  will  be  re- 
ferred to  later. 

The  question  at  once  arose  in  the  writer's  mind 
as  to  whether  the  virulence  of  his  saliva,  as  shown 
by, these  experiments,  was  an  individual  pecu- 
liarity, due  perhaps  to  some  antecedent  event  in 
his  personal  history,  —  e.  g.,  an  attack  of  yellow 
fever  experienced  in  1875  ;  or  whether  it  was  due 
to  circumstances  relating  to  his  environment  at 
the  time,  —  e.  g.?  residence  in  a  Southern  city  dur- 
ing the  summer  months,  and  constant  contact  with 
putrefying  organic  material  in  the  course  of  his 
experimental  studies ;  or  whether  it  was,  possibly,' 
a  general  fact  that  human  saliva  is  fatal  to  rabbits, 
when  injected  beneath  their  skin. 

These  questions  could  evidently  only  be  settled 
by  the  experimental  method,  and  a  visit  was  made 
to  the  city  of  Philadelphia,  during  the  month  of 
January,  1881,  for  the  purpose  of  pursuing  the 
investigation,  with  the  kind  assistance  of  Dr. 
Formad,  in  the  laboratory  of  the  Medical  Depart- 
ment of  the  University  of  Pennsylvania,  Here, 
eleven  inoculation  experiments  demonstrated 
(a)  that  the  virulence  noted  was  not  due  to  sea- 
son or  to  locality,  —  as  the  same  result  followed 
inoculations  made  in  Philadelphia  during  the  win- 
ter months  as  had  been  obtained  by  similar  in- 


SEPTICAEMIA  IN  RABBITS.  357 

oculations  in  New  Orleans  during  the  heat  of 
summer ;  (#)  that  this  virulence  was  not  an  indi- 
vidual peculiarity,  inasmuch  as  eleven  rabbits, 
inoculated  with  the  saliva  of  six  different  persons, 
gave  eight  deaths  and  three  negative  results.  As 
no  account  was  made  of  the  previous  history  of 
these  rabbits,  it  is  now  impossible  to  say  whether 
these  negative  results  are  to  be  ascribed  to  a  less 
degree  of  virulence  of  the  saliva  injected,  or  to 
antecedent  experimental  injections  which  had  pos- 
sibly been  made  in  the  laboratory,  and  which 
afforded  these  animals  protection.  Still,  a  differ- 
ence in  the  degree  of  virulence  was  shown  by  the 
fact  that  in  these,  and  in  numerous  subsequent 
experiments,  the  writer's  saliva  has  never  failed  to 
kill  unprotected  rabbits  within  forty-eight,  or  at  most 
sixty  hours  ;  while  in  a  considerable  number  of 
experiments  with  the  saliva  of  other  persons,  there 
have  been  several  failures  to  kill ;  and  in  other 
cases  the  fatal  result  has  been  delayed  to  three  or 
four  days,  and  even  longer.  This  difference  could 
not  be  accounted  for  as  being  connected  with  un- 
sound teeth  or  the  use  of  tobacco.  The  writer 
has  sound  teeth,  and  the  secretions  which  accumu- 
late in  his  mouth  are  normal  in  appearance  and 
reaction,  and  free  from  any  odor. 

The  facts  thus  far  observed  seemed  to  be 
worthy  of  fuller  investigation,  with  a  view  to 
explaining  the  cause  of  this  virulence ;  and  in  the 
month  of  March  further  experiments  were  com- 
menced in  the  biological  laboratory  of  Johns  Hop- 


358  BACTERIA'  IN  INFECTIOUS  DISEASES. 

kins  University.  The  result  of  these  was  very 
definite,  and  experimental  proof  was  obtained  that 
the  fatal  result  is  due  to  the  presence  of  a  micro- 
coccus  in  the  saliva,  which  finds  the  conditions 
favorable  for  its  rapid  multiplication  when  intro- 
duced beneath  the  skin  of  a  rabbit,  and  which 
gives  rise  to  an  infectious  form  of  septicaemia,  in 
which,  owing  to  its  presence  in  the  blood  of  an 
animal  recently  dead,  a  minimum  quantity  of 
blood  taken  from  the  heart  of  a  victim  to  the 
disease,  is  infallibly  fatal  to  other  rabbits  when 
introduced  in  like  manner  into  the  subcutaneous 
cellular  tissue.  The  evidence  in  support  of  the 
etiological  role  of  the  micrococcus  in  this  induced 
septicaemia  of  the  rabbit  is  of  the  same  nature  as 
that,  just  recorded,  in  the  form  of  septicaemia  of 
the  mouse  studied  by  Koch,  and  as  that  by  which 
the  anthrax  bacillus  has  been  shown  to  be  the 
cause  of  anthrax.  It  may  be  summarized  as 
follows  :  — 

(a)  The  poison  is  proved  to  be  participate  by  filtration 
experiments. 

(6)  The  virulent  fluids,  saliva,  blood,  culture-fluids, 
all  contain  a  micrococcus.  (See  Figs.  1  and  3, 
Plate  VI.) 

(c)  These  fluids  produce  an  identical  result,  and  this 
result  does  not  vary  according  to  the  quantity  of  mate- 
rial introduced,  as  is  the  case  where  poisonous  proper- 
ties depend  upon  the  presence  of  a  chemical  poison. 

(d)  Those  agents  which  destroy  the  vitality  of  the 
micrococcus  destroy  the  virulence  of  the  fluids  contain- 
ing it. 


SEPTICAEMIA  IX  RABBITS.  359 

(e)  Pure  cultures  of  the  micrococcus  are  as  virulent  as 
the  saliva,  in  the  first  instance,  or  the  blood  of  a  rabbit 
killed  by  introducing  this  fluid  beneath  its  skm. 

I  have  usually  injected  from  5  to  20  minims 
of  saliva  (mixed  salivary  secretions  and  buccal 
mucus  as  found  in  the  mouth),  and,  as  stated  in 
my  first  report,  this  has  infallibly  proved  fatal  (to 
unprotected  animals).  But  in  an  experiment  made 
in  Baltimore,  a  single  minim  of  saliva  mixed  with 
five  minims  of  distilled  water  was  injected  into  each 
of  five  young  rabbits.  Three  of  the  five  died  within 
the  usual  time — forty-eight  hours — with  the  usual 
symptoms,  and  presenting  the  characteristic  patho- 
logical appearances.  The  other  two  showed  no  ill 
effect  from  the  injection. 

The  following  quotation  from  my  first  report 
shows  the  character  of  this  fatal  infectious  disease, 
which,  originating,  as  in  the  above-mentioned  ex- 
periment, from  the  introduction  of  a  single  drop  of 
human  saliva  beneath  the  skin  of  one  of  these  ani- 
mals, may  be  transmitted  indefinitely  from  one  to 
'another  by  successive  inoculations. 

"The  course  of  the  disease  and  the  post  mortem 
appearances  indicate  that  it  is  a  form  of  septicaemia. 
Immediately  after  the  injection  there  is  a  rise  of  tem- 
perature, which  in  a  few  hours  may  reach  2°  to  3°  C. 
(3.6°  to  5.4°  Fahr.) ;  the  temperature  subsequently 
falls,  and  shortly  before  death  is  often  several  degrees 
below  the  normal.  There  is  loss  of  appetite  and  marked 
debility  after  twenty-four  hours,  and  the  animal  com- 
monly dies  during  the  second  night  or  early  in  the  morn- 


360  BACTERIA  IN  INFECTIOUS  DISEASES. 

ing  of  the  second  day  after  the  injection.  Death  results 
still  more  quickly  when  the  blood  from  a  rabbit  recently 
dead  is  injected.  Not  infrequently  convulsions  imme- 
diately precede  death. 

"The  most  marked  pathological  appearance  is  a  diffuse 
inflammatory  oedema  or  cellulitis,  extending  in  all  direc- 
tions from  the  point  of  injection,  but  especially  to  the 
dependent  portions  of  the  body.  Occasionally  there  is 
a  little  pus  near  the  puncture,  but  usually  death  occurs 
before  the  cellulitis  reaches  the  point  of  producing  pus. 
The  subcutaneous  connective  tissue  contains  a  quantity 
of  bloody  serum,  which  possesses  virulent  properties, 
and  which  contains  a  multitude  of  micrococci.  .  There 
is  usually  more  or  less  inflammatory  adhesion  of  the 
integument  to  the  subjacent  tissues.  The  liver  is  some-' 
times  dark  colored  and  gorged  with  blood,  but  more 
frequently  is  of  a  lighter  color  than  normal,  and  contains 
much  fat.  The  spleen  is  either  normal  in  appearance  or 
enlarged  and  dark  colored.  Changes  in  this  organ  are 
more  marked  in  those  cases  which  are  of  the  longest 
duration.  In  certain  cases  dark-colored  pigment  has 
been  found  in  the  spleen,  resembling  that  which  has 
been  supposed  to  be  characteristic  of  malarial  fever. 
The  blood  is  dark-colored,  usually  fluid,  and  there  is  a 
tendency  to  agglutination  of  the  red  corpuscles. 

"The  blood  commonly  contains  an  immense  number  of 
micrococci,  usually  joined  in  pairs,  and  having  a  diam- 
eter of  about  0.5  //,.  These  are  found  in  blood  drawn 
from  superficial  veins,  from  arteries,  and  from  the  cavi- 
ties of  the  heart  immediately  after  death,  and  in  a  few 
cases  their  presence  has  been  verified  during  life.  Ob- 
servations thus  far  ma'le  indicate,  however,  that  it  is 
only  during  the  last  hours  of  life  that  these  parasites 
multiply  in  the  circulating  fluid,  and  in  a  certain  pro- 
portion of  the  cases  a  careful  search  has  failed  to  reveal 


SEPTICAEMIA   IN  RABBITS.  361 

their  presence  in  post  mortem  examinations  made  imme- 
diately upon  the  death  of  the  animal.  This  organism, 
however,  is  invariably  found  in  great  abundance  in  the 
serum  which  exudes  in  considerable  quantities  from 
the  cedematous  connective  tissue  when  an  incision  is 
made  through  the  integument  over  any  point  involved 
in  the  inflammatory  oedema  extending  from  the  original 
puncture." 

In  this,  as  in  other  infectious  diseases,  the  final 
proof  that  micro-organisms  present  in  infective 
material  are  the  cause  of  the  train  of  morbid  phe- 
nomena constituting  the  disease,  is  to  be  obtained 
only  from  inoculation  experiments  with  pure  cul- 
tures of  these  micro-organisms.  This  proof  was 
obtained  for  the  disease  in  question  during  my 
Baltimore  experiments  (1881),  and  a  repetition  of 
these  experiments  in  San  Francisco  (1882)  has 
fully  confirmed  the  results  first  reported,  as  is 
shown  by  the  following  record  of  experiments  :  — 

"Exp.  No.  1.  — San  Francisco,  July  6,  1882.  In- 
jected twenty-five  minims  of  my  own  saliva  beneath 
the  skin  of  left  flank  of  each  of  two  half-grown  rabbits. 
Result.  —  Both  rabbits  were  found  dead  on  the  morning 
of  July  8.  Post  mortem  examination  at  8  A.  M.  showed 
extensive  cellulitis,  dilatation  of  superficial  veins,  and 
abundant  effusion  of  serum  in  subcutaneous  connec- 
tive tissue.  This  serum  and  the  blood  obtained  from 
the  heart,  swarmed  with  micrococci  exactly  resembling 
those  heretofore  found  under  similar  circumstances  in 
New  Orleans,  Philadelphia,  and  Baltimore.1  One  rab- 

1  See  Special  Report  to  Nat.  Board  of  Health  in  Bulletin  N.  B.  of  H. 
April  30, 1881. 


362  BACTERIA  IN  INFECTIOUS  DISEASES. 

bit  was  still  warm,  the  other  had  evidently  been  dead 
for  several  hours.  The  spleen  of  the  first  was  but 
slightly  enlarged,  that  of  the  second  was  swollen,  hard, 
and  dark-colored  in  patches.  No  pigment  found  in 
either  spleen. 

"  A  culture-flask  containing  sterilized  rabbit  bouillon 
was  inoculated  with  blood  from  the  heart  of  rabbit  No. 
1.  At  the  end  of  twenty-four  hours  the  fluid  in  this 
flask  swarmed  with  micrococci.  A  second  culture-flask 
was  inoculated  from  this,  a  third  from  the  second,  and 
so  on  to  the  sixth,  twenty-four  hours  being  allowed  in 
each  case  for  the  development  of  the  micrococcus. 
[The  flasks  were  placed  in  a  culture-oven  maintained  at 
a  temperature  of  100°  Fahr.  For  the  author's  method 
of  manipulation  see  p.  177.] 

44  Exp.  No.  2.  —  July  15.  Injected  twenty-five  min- 
ims of  above  culture-fluid  (sixth)  beneath  the  skin  of 
a  half-grown  rabbit.  Result.  —  This  rabbit  died  during 
the  night  of  July  18,  and  upon  post  mortem  examination 
was  found  to  present  the  same  pathological  appearances 
as  in  the  former  experiment, — viz.,  extensive  cellu- 
litis,  with  effusion  of  serum  swarming  with  micrococci. 
The  blood  also  contained  the  micrococci  in  abundance  ; 
spleen  somewhat  enlarged  and  dark-colored ;  no  pig- 
ment found. 

44  A  new  culture  was  started  from  the  blood  of  this 
rabbit  by  introducing  a  minute  quantity  of  blood  di- 
rectly from  the  left  auricle  into  a  culture-flask  contain- 
ing sterilized  rabbit  bouillon.  As  before,  this  was  carried 
by  successive  inoculations  from  one  flask  to  another  to 
the  sixth  culture,  the  culture-flask  being  in  each  in- 
stance placed  in  an  oven  at  100°  Fahr.,  for  twenty-four 
hours,  for  the  development  of  the  micrococcus. 

44  Exp.  No.  3.  —  July  26.  Ten  minims  of  above-cul- 
ture (No.  6)  was  injected  beneath  the  skin  of  a  half- 


SEPTICAEMIA  IN  RABBITS.  363 

grown  rabbit.  Result.  —  The  animal  died  at  10  A.  M., 
July  29,  and  a  post-mortem  examination  was  made  at 
once.  The  subcutaneous  cellular  tissue  was,  as  usual, 
infiltrated  with  serum  containing  the  micrococcus, 
which  was  also  present  in  the  blood  in  large  numbers. 
The  spleen  was  very  large  and  dark-colored.  A  por- 
tion was  removed  for  microscopical  examination,  and 
the  remainder  left  in  situ,  the  animal  being  so  placed 
that  it  should  be  dependent.  No  pigment  was  found 
in  the  portion  first  removed,  but  the  presence  of  black 
pigment  in  the  portion  left  in  situ  was  verified  the  fol- 
lowing day  (removed  at  9  A.  M.). 

44  The  culture-fluid  (No.  6)  used  in  experiment  No.  3 
(July  26)  was  laid  aside  in  an  hermetically  sealed 
culture-flask  until  September  12,  when  a  minute  drop 
was  used  to  inoculate  sterilized  bouillon  in  culture-tube 
No.  7.  This,  placed  in  a  culture-oven  at  100°  Fahr.  for 
twenty-four  hours,  became  clouded,  and  upon  micro- 
scopical examination  proved  to  be  pervaded  by  the 
identical  micrococcus  heretofore  described  and  photo- 
graphed. A  drop  of  culture  No.  7  was  used  to  inocu- 
late culture  No.  8,  and  the  next  day,  this,  being  also 
pervaded  by  the  micrococcus,  was  used  in  the  following 
experiment :  — 

44  Exp.  No.  4.  —  September  14.  Injected  ten  minims 
of  culture  No.  8  into  a  full-grown  rabbit.  Result. — 
This  animal  died  at  9  A.  M.,  September  15,  and  a  micro- 
scopical examination  made  at  once  demonstrated  the 
presence  of  the  micrococcus  in  great  numbers  in  the 
blood  and  in  effused  serum  in  the  subcutaneous  con- 
nective tissue.  The  usual  diffuse  cellulitis,  extending 
from  the  point  of  inoculation,  was  present;  spleen 
small,  and  contained  no  pigment. 

44  Remarks.  —  This  experiment  shows  that  the  micro- 
coccus  retained  its  vitality  and  its  full  virulence  at  the 


364  BACTERIA  IN   INFECTIOUS   DISEASES. 

end  of  six  weeks  ;  and,  very  conclusively,  that  the  viru- 
lence of  the  culture-fluid  is  due  to  the  presence  in  it  of 
the  micrococcus,  and  not  to  a  hypothetical  chemical 
virus  found  in  the  first  instance  in  the  saliva,  and  sub- 
sequently in  the  blood  of  a  rabbit  inoculated  with  this 
fluid.  For  the  benefit  of  those  who  have  not  calculated 
the  degree  of  dilution  which  such  a  hypothetical  chemi- 
cal virus  would  undergo  in  such  a  series  of  culture 
experiments,  I  submit  the  following  simple  calculation : 
My  culture-tubes  contain  about  a  fluidrachm  of  steril- 
ized bouillon.  The  amount  of  blood  introduced  into 
culture  No.  1,  as  seed,  was  considerably  less  than  a 
minim,  but  for  convenience  I  will  suppose  that  one 
minim  is  used  each  time  to  start  a  new  culture,  —  that 
is,  the  original  material  is  diluted  60  times  in  the  first 
culture,  3600  times  in  the  second,  216,000  times  in  the 
third,  and  in  the  eighth  culture  it  will  be  present  in  the 
proportion  of  one  part  in  167,961,600,000,000.  Yet  a 
few  minims  of  this  eighth  culture  possess  all  the  viru- 
lence of  the  first.  .  .  . 

41  To  convince  those  who  still  question  the  etiological 
role  of  the  micrococcus  in  the  infectious  disease  of  rabbits 
at  present  under  consideration,  it  would  hardly  be  worth 
while  to  carry  our  culture  experiments  further,  as  has 
been  done  by  Pasteur  and  other  pioneers  in  this  field  of 
investigation,  —  e.  g.,  in  anthrax  and  in  fowl-cholera.  I 
therefore  turn  to  another  line  of  proof. 

44 1  have  fixed  very  definitely  the  thermal  death-point 
of  this  septic  micrococcus.  It  is  killed  by  exposure  for 
ten  minutes  to  a  temperature  of  140°  Fahr.  It  survives 
exposure  to  130°  for  the  same  time.  This  is  the  result 
of  a  considerable  number  of  experiments,  and  is  estab- 
lished by  the  simple  method  of  exposing  a  culture-fluid 
containing  the  micrococcus,  and  enclosed  in  a  hermeti- 
cally-sealed tube,  to  a  given  temperature  for  the  time 


SEPTICAEMIA  IN  RABBITS.  365 

adopted  as  a  standard,  —  ten  minutes,  —  and  then  using 
the  fluid  to  inoculate  sterilized  bouillon  in  another  tube. 
This,  being  placed  in  a  culture  oven  for  twenty-four 
hours,  remains  transparent  and  unchanged  if  the  seed 
has  been  killed,  but  is  clouded  and  pervaded  by  the 
micrococcus  if  its  vitality  was  not  destroyed. 

"  In  my  first  series  of  experiments  (Baltimore,  1881) 
I  found  that  boiling  destroys  the  virulence  of  blood  from 
a  septicsemic  rabbit.  Having  now  fixed  with  precision 
the  thermal  death-point  of  the  micrococcus,  the  next  step 
was  evidently  to  see  whether  this  temperature  also 
destroys  the  virulence  of  the  fluid  containing  it.  To 
test  this  matter,  the  following  experiment  was  made 
with  the  second  culture  from  the  blood  of  the  rabbit 
which  died  September  15,  as  above  reported. 

"  Exp.  No.  5,  September  17.  —  Injected  ten  minims 
of  culture  No.  2  beneath  the  skin  of  a  small  spotted 
rabbit,  also  ten  minims  of  the  same  culture-fluid,  heated 
to  140°  Fahr.  for  ten  minutes,  beneath  the  skin  of  a 
small  white  rabbit  of  the  same  litter.  Result.  —  The 
small  spotted  rabbit  was  found  to  be  dying  the  follow- 
ing morning  at  eight  o'clock.  It  was  killed  bv  breaking 
up  the  medulla,  and  the  blood  from  the  heart  examined 
immediately.  This  contained  the  micrococcus  in  abun- 
dance, as  did  also  a  quantity  of  serum  contained  in  the 
pleural  cavity  and  effused  serum  in  the  subcutaneous 
cellular  tissue.  The  small  white  rabbit,  injected  at  the 
same  time  with  the  same  culture-fluid,  heated  to  140°  for 
ten  minutes,  did  not  seem  to  experience  the  slightest  ill 
effect  from  the  injection,  and  to-day  (September  24) 
remains  in  apparent  good  health ;  that  is,  the  virulence 
of  the  culture-fluid  used  in  this  experiment  was  destroyed 
by  the  exact  temperature  which  I  had  previously  determined 
to  be  fatal  to  the  micrococcus."  1 

1  Quoted  from  communications  to  the  "  Philadelphia  Medical  Times/' 
of  September  9  and  November  4,  1882. 


366  BACTERIA  IN  INFECTIOUS  DISEASES. 

If  further  proof  is  required,  it  is  to  be  found 
in  the  comparison  which  the  writer  has  made 
in  his  paper  on  the  "  Germicide  Value  of  Certain 
Therapeutic  Agents,"  l  of  the  action  of  germicides 
upon  the  micrococcus  as  contained  in  culture-fluids, 
as  compared  with  the  power  of  the  same  agents 
to  destroy  the  virulence  of  septic  blood,  as  tested 
by  inoculation  experiments  (/.  c.  p.  342). 

It  is  worthy  of  remark  that,  in  the  very  numer- 
ous culture-experiments  made  by.  the  writer  at 
different  times  and  places,  in  which  a  sterilized 
culture-fluid  has  been  inoculated  with  a  minute 
quantity  of  blood  from  the  heart  of  a  rabbit  just 
dead  from  the  form  of  septicaemia  under  consider- 
ation, or  from  a  vein,  or  from  effused  serum  in  the 
cellular  tissue,  the  micrococcus  already  described 
has  always  been  found  in  the  culture  after  twenty- 
four  hours'  incubation,  and  it  has  invariably  been  found 
alone,  no  other  micro-organism  having  been  associ- 
ated with  it  in  any  case.  This  is  offered  as  very 
satisfactory  proof  of  the  reliability  of  the  method 
adopted,  —  i.  e.,  as  regards  the  possibility  of  acci- 
dental contamination ;  and  of  the  constant  presence 
of  this  particular  micrococcus  in  the  fluids  men- 
tioned. 

Shortly  before  the  publication  of  the  writer's 
first  report  relating  to  this  form  of  septicaemia  in 
the  rabbit,  Pasteur  announced  to  the  French  Acad- 
emy his  discovery  of  a  "  new  disease  "  resulting 

1  American  Journal  of  the  Medical  Sciences,  No.  CLXX.,  April, 
1  b  s j . 


SEPTICAEMIA  IN  RABBITS.  367 

from  the  injection  beneath  the  skin  of  a  rabbit  of 
buccal  mucus,  gathered  by  means  of  a  camels- 
hair  brush  from  the  mouth  of  a  child  which  died 
in  one  of  the  hospitals  of  Paris  from  hydrophobia 
(December  11,  1880).  The  material  was  obtained 
four  hours  after  death;  the  brush  used  to  collect  it 
was  washed  out  in  water,  and  the  fluid  injected 
into  two  rabbits.  These  were  found  dead  Decem- 
ber 13.  Other  rabbits  were  inoculated  with  blood 
from  these,  and  their  death  with  the  same  symp- 
toms proved  that  an  infectious  disease  had  been 
produced. 

There  can  no  longer  be  any  doubt  that  this  dis- 
ease was  identical  with  that  which  the  writer  had 
previously  produced  by  inoculating  rabbits  with 
his  own  saliva ;  and,  consequently,  that  the  natural 
inference  of  Pasteur  that  this  "  new  disease  "  was 
due  to  the  fact  that  the  child  from  whom  the 
material  which  produced  it  was  obtained  had  died 
of  hydrophobia,  was  an  error.  Subsequent  experi- 
ments by  Yulpian  and  others  soon  made  it  plain 
that  a  mistake  had  occurred,  and  nothing  more  has 
been  heard  from  Pasteur  concerning  his  new  dis- 
ease. But  the  results  reported  are  entirely  in 
accord  with  the  deductions  of  the  writer  as  to  the 
etiological  role  of  the  micrococcus. 

Pasteur  describes  this  as  follows  :  — 

"This  organism  is  sometimes  so  small  that  it  may 
escape  a  superficial  observation.  Its  form  does  not  differ 
from  that  of  many  other  microscopic  beings.  It  is  an 
extremely  short  rod  a  little  compressed  towards  the 


368  BACTERIA  IN  INFECTIOUS  DISEASES 

middle,  resembling  a  figure  8,  and  of  which  the  diameter 
of  each  half  often  does  not  exceed  a  half  a  thousandth 
of  a  millimeter.  Each  of  these  little  particles  is  sur- 
rounded at  a  certain  focus  with  a  sort  of  aureole  which 
corresponds,  perhaps,  to  a  material  substance." 

The  possibility  that  this  appearance  is  due  to 
diffraction  is  considered,  but  Pasteur  inclines  to 
the  opinion  that  in  the  case  in  question  it  is  due 
to  a  mucous  substance  which  surrounds  the  organ- 
ism. (See  Fig.  3,  Plate  VI.) 

At  the  meeting  of  the  French  Association  for 
the  Advancement  of  Science,  in  1881,  Chauveau, 
in  his  address  as  President  of  the  Association, 
says :  "  For  a  moment  we  hoped  that  Pasteur 
had  determined  thus  [by  artificial  cultivation]  the 
virus  of  hydrophobia,  but  he  tells  us  himself  that  he 
has  only  cultivated  a  new  septic  agent"  Koch's  recent 
attack  upon  Pasteur,  in  which  he  makes  much  of 
this  mistake,  seems  a  little  out  of  place  in  view  of 
this  frank  confession  made  more  than  two  years 


ago. 


The  last-named  observer  has  also  encountered 
this  form  of  induced  septicaemia  in  the  rabbit,  and 
has  shown  that  the  micrococcus  which  produces  it 
is  not  alone  found  in  human  saliva.  This  was  a 
priori  to  have  been  expected,  and  the  writer  has 
never  supposed  that  the  human  mouth  was  the 
only  habitat  of  the  micro-organism  in  question. 
But  being  unwilling  to  generalize  from  insufficient 
data,  he  has  not  even  claimed  that  all  human  saliva 
is  fatal  to  rabbits,  but  has  taken  pains  to  say,  in 


SEPTICAEMIA  IN  RABBITS.  369 

recording  his  results,  "my  saliva/'  injected  in  such 
or  such  an  amount,  produces,  etc. 

Koch  gives  the  following  account  of  the  occur- 
rence of  this  interesting  disease  in  the  course  of 
his  experimental  inoculations:  — 

44  After  injection  of  putrid  infusion  of  meat  into 
rabbits,  I  have  twice  obtained  a  general  infection  of 
another  sort  in  which  metastatic  deposits  do  not  occur 
[as  is  the  case  in  the  disease  described  by  him  as  pyaemia 
in  rabbits],  and  which  I  would  therefore  describe,  in 
contrast  to  the  foregoing,  as  septicaemia.  This  infusion, 
like  the  putrid  fluids  used  in  the  earlier  experiments, 
contained  numbers  of  bacteria  of  the  most  various  forms. 
When  injected  under  the  skin  of  the  back  of  a  rabbit  it 
produces  an  extensive  putrid  suppuration  of  the  sub- 
cutaneous cellular  tissue,  and  the  animal  dies  in  three 
da}'s  and  a  half.  At  the  ichorous  spot,  which  must,  on 
account  of  its  size,  be  looked  upon  as  the  immediate 
cause  of  death  (owing  to  absorption  of  poisonous  material 
in  solution),  the  same  variety  of  bacteric  forms  was 
present  as  in  meat  infusion.  At  the  border  of  this  spot 
the  cellular  tissue  was  infiltrated  with  a  slightly  turbid 
watery  fluid  which  contrasted  strikingly  with  the  brown- 
ish ichor  in  the  vicinity  of  the  place  of  injection.  In 
this  oedema  fluid  great  numbers  of  micrococci  of  con- 
siderable size  and  of  an  oval  form  were  almost  the  only 
organism  observed.  In  the  blood  also  similar  micrococci 
were  found,  though  only  in  small  numbers.  Further, 
in  the  papilli  of  the  kidney  and  in  the  greatly  enlarged 
spleen,  some  of  the  small  veins  were  blocked  for  short 
distances  with  these  oval  micrococci. 

4'  Two  drops  of  this  oedematous  fluid  were  now  in- 
jected under  the  skin  of  the  back  of  a  second  rabbit. 
The  animal  died  in  twenty-four  hours,  and  here,  in  the 

24 


370  BACTERIA  IN  INFECTIOUS   DISEASES. 

neighborhood  of  the  place  of  injection,  not  a  trace  of 
pus  could  be  observed.  On  the  other  hand,  slight  oedema, 
with  a  streaky  whitish  appearance  of  the  subcutaneous 
cellular  tissue,  extended  from  the  point  of  injection  to 
the  abdomen.  I,n  this  cedematous  cellular  tissue  lay 
numerous  flat  extravasations  of  blood  half  a  centimeter 
in  breadth,  the  vessels  around  being  greatly  distended. 
The  muscles  of  the  thigh  and  of  the  abdominal  walls 
were  also  interspersed  with  small  extravasations.  [These 
hemorrhagic  extravasations  were  common  also  in  the 
victims  of  the  writer's  experiments.]  In  the  heart  and 
lungs  no  alterations  were  found.  In  the  peritoneal 
cavity  no  fluid  was  present,  the  peritoneum  being  un- 
altered and  the  coils  of  intestine  not  glued  together. 
But  the  surface  of  the  intestine,  in  consequence  of  a 
number  of  small  subserous  extravasations,  presented  an 
appearance  as  if  injected  here  and  there  with  blood. 
The  spleen  was  also  very  considerably  enlarged.  In 
this  second  animal  the  oval  micrococci  were  alone  present 
in  the  cedematous  cellular  tissue,  all  the  other  bacteria 
having  disappeared.  The  number  of  these  organisms 
was  very  considerable,  many  of  the  small  veins  being 
completely  filled  with  them.  .  .  . 

44  These  micrococci  differ  from  the  micrococci  of 
pyaemia  very  markedly  as  regards  size,  and  in  most 
other  points.  Thus  they  never  enclose  the  blood  cor- 
puscles, even  when  they  have  accumulated  in  large 
numbers  in  the  interior  of  the  blood-vessels.  They 
rather  push  them  on  one  side.  They  do  not  cause  co- 
agulation of  the  blood,  and  thus  emboli  do  not  occur." 

The  experiments  made  by  the  writer  have  been 
repeated  by  Claxton,  who  says :  — 

"  I  shall  now  discuss  briefly  the  second  part  of  my 
argument,  namely,  what  constituent  of  the  saliva  pro- 


SEPTIC JEMI A  IN  RABBITS.  371 

duces  the  fatal  disease  ?  And  as  my  results  accord  so 
perfectly  with  those  obtained  by  Steinberg,  and  my  ex- 
periments in  this  direction  are  but  repetitions  of  his,  I 
shall  be  pardoned,  I  trust,  for  answering  the  question  in 
his  own  words. 

"  4  The  following  facts  demonstrate  that  the  phenomena 
detailed  result  from  the  presence  of  a  living  organism 
found  in  the  saliva,  namely,  a  micrococcus  which  multi- 
plies in  the  subcutaneous  connective  tissue,  and  also  in  the 
blood  shortly  before  or  after  death.'' " 

This  extended  account  of  the  disease  under  con- 
sideration, and  of  the  evidence  in  support  of  the 
writer's  first  announcement  as  regards  its  etiology, 
has  been  given  because  rabbits  are  extensively 
employed  in  experiments  relating  to  the  etiology 
of  infectious  diseases,  and  it  is  important  that 
those  who  enter  upon  such  investigations  should 
be  familiar  with  all  forms  of  disease  to  which  they 
are  subject.  And  also,  because,  notwithstanding 
the  experimental  evidence  adduced  in  favor  of  the 
view  that  the  virulence  of  normal  human  saliva  is 
due  to  the  micrococcus  described,  it  has  been  evi- 
dent that  there  has  been  considerable  incredulity 
as  to  the  correctness  of  this  conclusion,  on  the  part 
of  many  worthy  members  of  the  profession. 

We  have  seen,  in  the  article  on  septicaemia  in 
mice,  that  rabbits  are  not  susceptible  to  this  form 
of  septicaemia,  which  Koch  has  shown  to  be  due 
to  a  bacillus.  On  the  other  hand,  Koch  found 
that  the  injection  of  blood  from  a  septicaamic  rab- 
bit into  a  mouse,  although  it  killed  the  little 


372  BACTERIA  IN   INFECTIOUS  DISEASES. 

animal  in  thirty-seven  hours,  did  not  give  rise  to 
the  infectious  form  of  the  disease ;  for  a  second 
mouse,  which  was  inoculated  with  blood  from  the 
heart  of  the  first,  was  not  visibly  affected. 

In  a  limited  number  of  experiments  by  the 
writer,  in  which  his  own  saliva  was  injected  into 
animals  other  than  the  rabbit,  the  following  results 
were  obtained  :  — 

Injection  of  4  c.  c.  into  each  of  two  small  dogs  pro- 
duced local  abscesses  at  the  point  of  injection,  but  no 
other  noticeable  results.  A  dog  succumbed,  however, 
to  an  injection  of  1  c.  c.  of  serum  from  the  cellular  tis- 
sue of  a  rabbit  recently  dead. 

Injection  of  0.25  c.  c.  (each)  into  five  chickens  pro- 
duced no  result. 

Injection  of  0.75  c.  c.  (each)  into  three  guinea-pigs 
proved  fatal  to  two,  —  one  in  three,  and  one  in  seven 
days. 

Injection  of  0.5  c.  c.  into  five  rats  resulted  fatally  to 
one  only. 

These  results  correspond  with  those  reported  by 
Pasteur,  who  found  the  guinea-pig  less  susceptible 
than  the  rabbit ;  the  chicken  entirely  insuscepti- 
ble ;  and  the  dog  susceptible  to  injections  of  blood 
from  dead  rabbits. 

The  value  of  protective  inoculations  in  this  form 
of  septicaemia  has  been  brought  out  accidentally 
in  the  course  of  the  writer's  experiments ;. and  it 
li;i<  been  liis  intention  to  investigate  this  interest- 
ing subject  fully  by  the  experimental  method. 
This  he  has  not  yet  been  able  to  do,  and,  conse- 


SEPTIC^IMIA  IN  RABBITS.  373 

quently,  can  only  present  such  facts  as  have  been 
developed  by  experiments  made  with  a  different 
object. 

Two  rabbits  injected  with  full  doses  of  my 
saliva,  in  New  Orleans,  proved  to  be  insuscep- 
tible to  its  lethal  effects.  These  rabbits  had 
previously  received  the  following  experimental 
inoculations  :  — 

Rabbit  No.  1.  —  Received  October  7,  1.35  c.  c.  of 
swamp-culture  (organisms  from  swamp  mud  cultivated 
in  gelatine  solution  a  la  Klebs  and  Torumasi-Crudeli)  ; 
October  28,  1.3  c.  c.  of  spleen-culture  (from  a  rabbit 
which  died  from  an  injection  of  0.75  c.  c.  of  swamp- 
culture  in  gelatine  solution). 

Rabbit  No.  2.  —  Received  October  7,  1.35  c.  c.  of 
spleen-culture  ;  and  October  27,  1.26  c.  c.  of  spleen- 
culture,  which  injection  was  repeated  the  following 
day. 

On  the  12th  of  November  these  rabbits  both  received 
subcutaneously  1.26  c.  c.  of  my  saliva,  and.  except  for  a 
slight  febrile  reaction,  experienced  no  ill  effect  from  the 
dose. 

Baltimore,  May  24,  1881,  injected  into  a  large  rabbit 
1.25  c.  c.  of  virus,  not  disinfected,  from  a  rabbit  recently 
dead.  Result  negative.  This  rabbit  had  previously 
(May  13)  received  an  injection  of  0.5  c.  c.  of  virus 
mixed  half  an  hour  previously  with  sodium  hyposul- 
phite in  the  proportion  of  one  per  cent.  The  virus 
used  in  these  experiments  was  bloody  serum  from  a 
rabbit  just  dead,  which  was  proved  by  other  experi- 
ments to  be  fatal  to  unprotected  rabbits  in  the  smallest 
quantity.  Thus,  the  needle  of  a  hypodermic  syringe 
(Exp.  of  June  2,  1881)  was  dipped  into  the  blood  of 


374  BACTERIA  IN  INFECTIOUS  DISEASES. 

a  septicaemic  rabbit  just  dead,  which  was  proved  by 
microscopical  examination  to  contain  the  micrococcus 
in  abundance.  This  needle  was  then  introduced  under 
the  skin  of  another  rabbit,  which  died  within  forty- 
eight  hours,  and  presented  the  usual  appearances  of 
septicaemia. 

Protection  was  also  afforded  in  one  case  by  an  injec- 
tion of  virus  which  had  been  mixed  half  an  hour 
previously  with 'three  parts  of  95  per  cent,  alcohol. 

Finally,  I  take  the  liberty  of  quoting  the  case  of  Dr. 
Formad's  famous  buck  rabbit :  — 

"  There  remained  in  the  laboratory  a  number  of  living 
animals,  left  over  after  the  various  experimenters  of  my 
pathological  class  ceased  work,  at  the  conclusion  of  last 
winter's  term.  Among  the  number  was  a  buck  rabbit, 
which  had  been  largely  dosed,  by  my  friend  Claxton, 
with  saliva  of  some  kind.  Since  then,  during  the  last 
six  months,  this  same  rabbit  was  injected  subcutane- 
ously,  at  different  times,  with  all  the. articles  of  the 
following  bill  of  fare  : 

"1.  Human  saliva  (second  time);   2.  Cancer  juice; 

3.  Epidemic    diphtheritic    material    from    Michigan  ; 

4.  Bouillon,   containing   a  rich  crop  of  cultured   mi- 
crococci  from  the  same  material ;  5.  Diphtheritic  ma- 
terial from  a  fatal  case  in  the  city  ;    6.  Slough  from 
rabbit,  dead  from   diphtheria ;   7.  Slough  from  scarla- 
tinal sore  throat ;  8.  Slough  from  erysipelas ;  9.  Slough 
from  gangrene ;  10.  Cadaveric  poison  ;  11.  Feces  from 
typhoid   fever  case  ;    12.   Sputa  from   case   of  tuber- 
culosis." i 

It  is  pretty  evident  that  this  rabbit  was  pro- 
tected from  septic  poisoning;  and  the  case  is  ex- 

i  Philadelphia  Med.  Times,  Sept.  16,  1882,  p.  194. 


SEPTIC^MIA  IN  RABBITS.  375 

ceedingly  instructive,  not  only  as  illustrating  the 
value  of  protective  inoculations  against  septicae- 
mia, but  as  showing  the  importance  of  selecting 
rabbits  not  previously  experimented  upon  for 
experimental  studies  relating  to  the  etiology  of 
infectious  diseases. 

It  should  also  be  remembered  by  those  who 
undertake  experimental  investigations  of  this  na- 
ture, that  accidental  inoculation  may  occur,  or 
that  a  rabbit  may  suffer  a  non-fatal  attack  as  the 
result  of  contact  with  other  septicsemic  animals,  or 
from  being  placed  in  infected  cages.  Davaine 
long  since  recorded  the  fact  that  spontaneous 
septicaemia  occurred  among  his  rabbits  from  this 
cause ;  and  the  writer  has  also  lost  a  number  of 
rabbits  in  this  way,  while  others  of  the  same  lot 
recovered  after  a  brief  illness,  and  subsequently 
proved  to  be  protected  from  the  lethal  effects  of 
septic  virus. 

It  is  not  impossible  that,  in  man,  a  certain 
immunity  from  infectious  diseases,  the  epidemic 
prevalence  of  which  depends  upon  the  presence 
of  decomposing  organic  material  in  the  infected 
localities,  —  e.g.,  cholera,  yellow  fever,  diphtheria, 
—  may  be  acquired  by  exposure  to  septic  material 
which  lacks  the  infectious  character ;  i.  e.,  that  a 
tolerance  is  established  to  the  effects  of  the  chem- 
ical poison  or  poisons  which  are  evolved  as  a  result 
of  the  vital  activity  of  both  pathogenic  and  non- 
pathogenic  bacteria.  It  has  frequently  been  noted 
that  grave-diggers,  those  who  clean  sewers,  and 


376  BACTERIA  IN  INFECTIOUS   DISEASES. 

those  who  pursue  pathological  studies,  are  even 
less  liable  to  contract  the  diseases  mentioned  than 
those  members  of  the  community  who  are  not  so 
much  exposed  to  infection. 

SPREADING  ABSCESS  IN  RABBITS,  Koch :  — 

"  Coze  and  Feltz,  Davaine,  and  many  others,  have 
obtained  in  rabbits,  by  the  injection  of  putrid  blood,  an 
infective  septicaemic  disease.  I  have  therefore  repeated 
their  experiments.  I  have  not,  however,  succeeded  in 
producing  the  effects  produced  by  Davaine,  but  I  ob- 
served —  what  others  who  have  made  similar  experi- 
ments on  rabbits  have  already  noticed  —  that  in  these 
animals  the  formation  of  an  abscess  constantly  increas- 
ing in  extent,  may  occur  in  the  subcutaneous  cellular 
tissue  without  any  general  infection  taking  place.  Such 
animals  have  at  first  no  symptoms  of  disease ;  a  flat 
lentiform  hard  infiltration  at  the  seat  of  injection  is  all 
that  can  be  observed.  After  several  days  this  hardness 
extends  in  all  directions,  chiefly  downwards,  especially 
towards  the  abdomen  and  anterior  extremities.  The 
animal  at  the  same  time  emaciates  and  grows  feeble, 
and  dies  in  about  twelve  to  fifteen  days  after  the 
injection. 

"  The  post  mortem  examination  shows  the  presence, 
in  the  subcutaneous  tissue,  of  extensive  flat  abscesses 
with  cheesy  contents  ;  their  walls  bulge  in  various 
directions,  though  the  whole  remains  a  single  cavity. 
There  is  also  an  extreme  degree  of  emaciation,  but  no 
alteration  in  the  peritoneum,  intestine,  kidney,  spleen, 
liver,  heart,  or  lungs.  In  the  blood  the  white  corpus- 
cles are  greatly  increased  in  number,  but  no  bacteria 
can  be  found.  The  cheesy  contents  consist  of  a  finely 
granular  material,  and  scattered  about  in  this  are  nuclei 


SPREADING  ABSCESS   IN  RABBITS.  377 

undergoing  disintegration  ;  but  no  bacteria  can  be  defi- 
nitely  made  out.  Here,  then,  we  have  appearances 
similar  to  those  often  found  in  man,  and  much  used  as 
an  argument  against  the  parasitic  nature  of  such  morbid 
processes.  I  refer  to  abscesses  resulting  from  phleg- 
monous  inflammation,  which  must  be  regarded  as  infec- 
tive in  their  origin,  but  in  which  no  micro-organisms 
have  been  found. 

'•  When,  however,  portions  of  these  abscesses  are 
hardened,  and  examined  in  sections,  the  surprising 
result  is  obtained  that,  though  bacteria  are  not  present 
in  their  contents,  their  walls  are  everywhere  formed  by 
a  thin  layer  of  micrococci,  united  together  into  thick 
zoogloea  masses.  These  organisms  are  the  smallest  patho- 
genic rnicrococci  which  I  have  as  yet  observed.  In 
some  places  I  was  fortunate  enough  to  find  them  ar- 
ranged in  rows,  and  thus  I  was  able  to  measure  them  ; 
and  I  ascertained  that  they  were  about  .15  //,  in  diame- 
ter. (This  is,  of  course,  only  an  approximate  measure- 
ment.) .  .  . 

"  In  order  to  ascertain  whether  the  morbid  process 
here  designated  as  progressive  abscess  formation  could 
be  transmitted  from  one  animal  to  another,  rabbits  were 
injected  with  blood  taken  from  others  which  had  already 
died  of  this  disease.  These  injections  produced  no  ef- 
fect. A  small  quantity  of  the  cheesy  contents  of  the 
abscess  was  now  taken,  diluted  with  distilled  water,  and 
injected  under  the  skin  of  a  rabbit. .  These  resulted  ex- 
actly the  same,  — abscess  formation  in  this  animal  as  in 
the  first.  The  abscesses  spread  in  the  same  manner 
as  described  in  the  former  case,  and  caused  the  death  of 
the  animal  experimented  on  in  a  week  and  a  half.  From 
this  animal  the  disease  was  conveyed  to  a  third,  and  so 
on  through  several  in  succession. 

"  It  was  thus  demonstrated  that  the  disease  is  not 


378  BACTERIA  IN  INFECTIOUS   DISEASES. 

merely  occasioned  by  the  injection  of  a  considerable 
quantity  of  putrefying  blood,  but  is  of  a  decidedly  in- 
fective character.  The  assumption  made  above,  that 
the  micrococci  in  the  cheesy  contents  of  these  abscesses 
are  dead,  does  not  appear  in  keeping  with  this  result  of 
inoculation.  This  apparent  contradiction  may,  however, 
I  think,  be  cleared  up  ;  for  it  is  very  probable  that  these 
micrococci,  like  other  bacteria,  form  resting  spores 
(Dauersporen)  after  the  expiration  of  their  vegetative 
life,  and  that  these  bodies,  just  like  the  spores  of  ba- 
cillus, are  not  stained  by  aniline,  and  therefore  remain 
invisible  in  Canada  balsam.  The  infection  in  the  case 
referred  to  would  be  brought  about  by  such  spores."  l 

SWINE  PLAGUE  ;  le  rouget  ou  mal  rouge  des  pores 
(Pasteur);  infectious  pneumo-enteritis  of  the  pig 
(Klein).  In  a  recent  communication  (December 
4,  1882)  to  the  French  Academy,.  Pasteur  gives 
the  following  summary  of  results  obtained  in  an 
experimental  research  relating  to  the  above-men- 
tioned disease :  — 

" 1.  Swine  plague  (mal  rouge  des  pores)  is  produced 
by  a  special  microbe,  which  is  easily  cultivated  outside 
of  the  body  of  the  animal.  It  is  so  minute  that  it  may 
easily  escape  observation,  even  the  most  attentive.  It 
most  nearly  resembles  the  microbe  of  fowl-cholera,  its 
form  being  that  of  the  figure  8.  But  it  is  smaller  and 
l»->s  easily  seen,  and  differs  essentially  from  the  microbe 
of  fowl-cholera  in  its  physiological  properties.  It  has 
no  action  upon  fowls,  but  kills  rabbits  and  sheep. 

"II.  When  inoculated  in  a  pure  condition  into  pigs, 
in  quantities  almost  inappreciable,  it  promptly  gives  rise 

1  Traumatic  Infective  Diseases,  pp.  45-47. 


SWINE  PLAGUE.  379 

to  the  disease  and  to  death,  the  symptoms  being  the 
same  as  in  spontaneous  cases.  It  is  especially  fatal  to 
the  white  race  (improved  breed,  most  highly  valued  by 
those  who  raise  pigs). 

"  III.  In  1878  Dr.  Klein,  of  London,  published  an 
elaborate  research  upon  this  disease,  which  he  calls 
infectious  pneumo-enteritis  of  the  pig ;  but  this  author 
has  been  entirely  mistaken  as  to  the  nature  and  proper- 
ties of  the  parasite.  He  has  described  a  bacillus  with 
spores  as  the  microbe  of  this  disease,  which  he  describes 
as  being  even  larger  than  Bacillus  anthracis  (la  bacteride 
du  charbon).  This  is  very  different  from  the  true  mi- 
crobe of  swine  plague,  and  has  no  relation  to  the  etiol- 
ogy of  the  disease. 

"  IV.  After  assuring  ourselves,  by  direct  proof,  that 
the  disease  does  not  recur,  we  have  succeeded  in  in- 
oculating it  in  a  mild  form,  and  the  animal  has  subse- 
quently proved  to  be  protected  against  the  malignant 
form  of  the  disease." 

Neguin  and  Salmon  had  previously  reported 
their  failure  to  find  the  bacillus  of  Klein  in  the 
blood  and  other  infectious  fluids  obtained  from  ani- 
mals sick  with  this  disease,  and  the  constant  pres- 
ence of  a  minute  microeoccus  apparently  identical 
with  that  described  by  Pasteur. 

Salmon  says  that  blood  drawn  from  the  veins  of 
a  pig  affected  with  swine-plague  into  "capillary 
vacuum  tubes  "  was  quite  free  from  bacilli  at  the 
end  of  ten  days.  But  this  blood  swarmed  with 
micrococci,  single,  in  pairs  (Pasteur's  Fig.  8),  in 
chains,  and  in  zoogloea  masses.  Healthy  pigs  in- 
oculated with  this  blood  sickened  at  the  end  of 
seven  days  and  exhibited  the  characteristic  symp- 


380  BACTERIA  IN  INFECTIOUS  DISEASES. 

torns  of  the  disease.  These  inoculations  did  not, 
however,  produce  a  fatal  form  of  the  malady,  and 
Salmon  found  it  impossible  to  carry  the  virus 
beyond  a  second  generation,  even  by  inoculating 
pigs  which  had  never  before  been  exposed  to  the 
contagium. 

Dr.  Klein  has  recently  reasserted  his  belief  that 
this  disease  is  due  to  the  bacillus  described  by  him 
in  his  original  report,  and  has  given  additional 
experimental  evidence  in  favor  of  this  view  (Jour- 
nal of  Physiology,  Vol.  V.,  No.  1). 

SYPHILIS.  —  The  presence  of  bacteria  in  the 
initial  lesion  of  syphilis,  in  secondary  papules,  in 
syphilitic  new  growths,  and  in  the  secretions  of 
chancroids  and  syphilitic  ulcers,  has  been  noted  by 
numerous  observers.  But  the  descriptions  given 
by  different  individuals  are  not  entirely  in  accord 
as  to  the  morphological  characters  of  these  bacteria. 
According  to  some,  —  Hallier,  Klebs,  Bermann, — 
they  are  micrococci ;  while  others  have  found 
bacilli,  —  Birch-Hirschfeld,  Morison  ;  and  Salis- 
bury finds  a  fungus  —  his  Crypto,  syphilitica  —  in 
the  blood  as  well  as  in  the  local  lesions  of  syphilis. 

Birch-Hirschfeld  at  first  described  the  organisms 
found  by  him  in  syphilitic  growths  as  bacilli,  but 
has  since  become  convinced  that  they  are  oval 
micrococci  arranged  in  chains.  He  says  that  it  is 
more  difficult  to  distinguish  the  individual  elements 
in  the  chains  than  in  the  case  of  spherical  micro- 


SYPHILIS.  381 

cocci.  These  oval  elements  are  found  single,  in 
pairs,  or  in  chains  of  four  or  five,  which  greatly 
resemble  long  rods  with  rounded  ends.  This 
description  agrees  with  that  of  Aufrecht: 

"  For  the  demonstration  of  the  organisms  in  recent 
preparations,  Birch-Hirsclifeld  prefers  potash,  by  the 
clearing  action  of  which  the  niicrococci  are  visible  in 
the  tissue,  on  account  of  their  strong  refracting  power. 
In  a  broad  condyloma,  they  lie,  for  the  most  part,  in 
small  aggregations  in  the  papillae,  and  in  many  of  the 
cells  of  the  adjacent  layer  of  the  rete  Malpighii.  They 
may  be  readily  detected  in  the  juice  of  a  recently  ex- 
cised condyloma,  by  tinting  in  the  ordinary  way  ;  and 
of  the  various  staining  agents,  Birch-Hirschfeld  con- 
cludes that  fuchsin  and  gentian-violet  are  the  best.  In 
the  growths  in  internal  organs  the  smallest  micrococci 
are  most  abundant,  and  the  larger  forms  seen  in  the  con- 
dylomata  are  seldom  met  with.  In  gummatous  scars 
they  are  sought  for  in  vain.  In  more  recent  gummatous 
products  they  were  most  abundant  in  parts  which  had 
the  aspect  of  growing  granulation  tissue.  They  were 
partly  scattered,  partly  aggregated  into  groups,  which 
never  exceeded  a  granulation-cell  in  size  ;  they  were 
also  distinctly  seen  within  the  cells.  Many  epithelioid 
cells  seemed  to  have  their  nuclei  filled  with  these  or- 
ganisms." 1 

Dr.  Bermann  of  Baltimore  finds  in  absolutely 
fresh  specimens  of  indurated  chancres,  "  collections 
of  micrococci  and  fungoid  growths,  firmly  adhering 
to  and  partly  blocking  the  lumina  of  most  of  the 
lymphatic  vessels."  According  to  this  observer,  the 

1  London  Lancet,  December  2,  1882. 


382  BACTERIA  IN  INFECTIOUS  DISEASES. 

micrococci  of  syphilis  are  small,  strongly  refract- 
ing bodies,  resembling  those  described  by  Klebs. 

Recently  Dr.  Morison  of  Baltimore  has  made  a 
careful  study  of  the  bacteria  found  in  chancroids 
and  in  syphilitic  lesions,  in  the  wards  of  Professor 
Neumann  of  Vienna.  As  he  resorted  to  the  most 
approved  methods  of  staining,  and  seems  to  have 


Fig.  20. 
Hard  chancre  secretion  with  bacteria,  magnified  850  diameters.    (Drawn  by  Heitzmann. ) 

exercised  special  care  in  collecting  and  mounting 
his  material  for  microscopic  examination,  his  obser- 
vations are  of  value,  and  I  have  taken  the  liberty 
of  copying  his  figures  from  the  "  Maryland  Medical 
Journal"  of  January  1,  1883,  in  which  his  paper 
was  published.  (See  Figs.  20  and  21.) 

No  satisfactory  proof  has  yet  been  offered  in 
support  of  the  view  that  any  one  of  the  organisms 
above  described  is  the  veritable  germ  of  syphilis ; 


SYPHILIS.  383 

and  it  is  evident  that  the  greatest  caution  must  be 
exercised  in  drawing  any  conclusions  as  to  their 
etiological  import.  For  there  is  nothing  improbable 
in  the  supposition  that  tissues  of  a  low  grade  of 
vitality  may  be  invaded  by  parasites  which  have 
no  causal  relation  to  the  morbid  process;  and  in 
view  of  what  we  know  of  the  extended  distribu- 


Fig.  21. 
Soft  chancre  secretion  with  bacteria,  magnified  850  diameters.    (Drawn  by  Heitzmann.) 

tion  and  infinite  variety  of  organisms  of  this  class, 
their  absence  from  the  secretions  of  an  open  ulcer 
would  be  more  remarkable  than  their  presence. 
In  a  second  communication,  dated  March  23,  Dr. 
Morison  states  that  a  modification  of  his  method 
of  staining  has  enabled  him  to  demonstrate  that 
the  rods  seen  in  Fig.  20  are  really  formed  of 
closely  united  cocci,  corresponding  with  those  de- 
scribed by  Birch-Hirschfeld.  He  further  says :  — 


384  BACTERIA  IN  INFECTIOUS  DISEASES. 

"  The  result  of  these  recent  experiments  is  such  that  I  am  not 
only  forced  to  deny  the  pathogenic  nature  of  the  micro-organisms 
described  in  rny  first  communication,  but  also  to  add  that  I  am 
convinced  their  presence  in  the  secretions  was  due  to  external 
influences." 

Klebs  claims  to  have  produced  syphilis  in  the 
monkey,  and  Martineau  and  Hamoine  to  have 
communicated  the  disease  to  young  pigs  (Morison). 
But  with  these  exceptions,  so  far  as  the  writer  is 
aware,  attempts  to  inoculate  syphilis  in  the  lower 
animals  have  given  negative  results. 

TUBERCULOSIS.  —  The  experimental  researches 
of  Villeman,  Tappeiner,  Colmheim,  Toussaint,  and 
others,  having  apparently  established  the  fact  that 
tuberculosis  is  an  infectious  disease,  the  medical 
profession  was  not  unprepared  for  the  discovery, 
first  announced  by  Koch  in  the  spring  of  1882,  of 
a  parasitic  micro-organism  in  tuberculous  material, 
bearing  a  causal  relation  to  the  disease  in  question. 
Coming  from  Koch  this  announcement  had  great 
weight  and  at  once  received  the  most  attentive 
consideration  in  all  parts  of  the  civilized  world  ;  for 
he  was  already  well  known  to  be  both  a  skilful 
and  a  cautious  investigator. 

The  experimental  proof  offered  in  favor  of  the 
view  that  the  bacillus  discovered  in  the  sputum  of 
tuberculous  patients,  and  in  recent  tubercles  in  the 
lungs  and  elsewhere,  was  the  veritable  cause  of 
tuberculosis,  seemed  so  convincing,  that  it  might 
have  been  received  almost  without  question,  but 
for  the  fact  that  other  experimenters  had  pre- 


TUBERCULOSIS.  385 

viously  found  that  tuberculosis  in  animals  may 
result  from  inoculation  with  a  variety  of  organic 
products  of  non- tubercular  origin,  and  even  from 
the  inhalation  of  inorganic  particles ;  which  also  is 
recognized  as  a  cause  of  pulmonary  consumption 
in  man.  As  an  example  of  the  numerous  experi- 
ments of  this  kind,  we  may  refer  to  the  results 
obtained  by  Brunet,  who  inoculated  seven  rabbits 
with  cancer,  six  with,  simple  pus,  and  six  with 
tuberculous  material.  Of  those,  fourteen  became 
tuberculous,  namely,  six  of  those  inoculated  with 
cancer,  three  of  those  inoculated  with  pus,  and 
five  of  those  inoculated  with  tuberculous  matter. 

Schottelius  found  that  miliarj7'  nodules  in  the 
lungs  resulted,  in  dogs,  alike  from  inhalation  of 
pulverized  —  spray  —  sputum  of  bronchitis  and  of 
phthisis. 

Toussaint  affirms  that  the  tubercular  deposits 
resulting  from  inoculation  with  non-tubercular 
material  are  not  infectious,  and  that  experimental 
pseudo-tuberculosis  may  be  distinguished  from 
tuberculosis  proper  by  inoculation  experiments, 
although  the  pathological  anatomy  of  the  two 
diseases  is  identical. 

Koch,  on  the  other  hand,  does  not  admit  that 
tuberculosis  can  be  produced  by  material  from 
which  living  tubercle  bacilli  or  their  spores  are  un- 
questionably excluded.  In  his  own  experiments 
he  found  that  in  all  cases  where  the  material  used 
for  inoculation  contained  living  bacilli  or  spores, 
the  result  was  positive  in  animals  liable  to  infec- 

25 


386  BACTERIA  IN  INFECTIOUS  DISEASES. 

tion ;  while  when  the  material  inoculated  did  not 
contain  these  bacilli  or  their  spores,  a  negative 
result  was  obtained.  Thus,  in  several  cases,  ex- 
periments were  performed  with  the  contents  of  a 
scrofulous  gland  and  with  various  other  material 
proved  by  examination  to  be  free  from  bacilli,  and 
in  no  instance  did  tuberculosis  follow.  The  posi- 
tive results  obtained  by  other  experimenters  with 
non-tuberculous  material  are  explained  by  the  sup- 
position that  tubercle  bacilli  or  their  spores  have 
been  introduced  at  the  same  time.  It  is  evident 
that  this  accidental  inoculation  would  be  very  apt 
to  occur  in  laboratories  where  tuberculous  animals 
had  been  kept  under  observation,  and  especially 
where  proper  precautions  are  not  taken  as  regards 
cleanliness  of  the  cages  in  which  animals  are  kept, 
and  the  isolation  of  those  which  are  subjected  to 
inoculation  experiments. 

According  to  Koch,  the  tubercle  bacillus  is  a 
slender  rod  from  a  quarter  to  a  half  of  the  diameter 
of  a  blood-corpuscle  in  length,  and  presents  certain 
distinctive  characters  as  regards  its  behavior  with 
staining  reagents.  The  various  methods  of  stain- 
ing this  bacillus  are  given  in  PART  THIRD  of  the 
present  volume.  The  bacilli  are  found  in  consider- 
able numbers  in  tubercles  of  recent  formation, 
more  especially  at  the  border  of  the  cheesy  masses. 
They  are  abundant  in  the  giant-cells,  and  seem  to 
possess  a  special  relation  to  these  cells.  They  are 
not  so  abundant  in  old  tubercles,  although  they  are 
seldom  entirely  absent.  By  placing  a  small  por- 


TUBERCULOSIS.  387 

tion  of  a  recent  tubercle  in  blood-serum  or  distilled 
water,  they  may  be  recognized  with  a  suitable 
objective  and  illuminating  apparatus,  without  the 
use  of  staining  reagents.  An  examination  made 
under  these  circumstances  shows  that  the  bacilli 
are  motionless,  and  in  some  rods  spores  of  oval 
form  may  be  distinguished.  At  the  time  of  his 
first  report,  Koch  had  examined  in  man,  "  Eleven 
cases  of  miliary  tuberculosis,  twelve  cases  of  cheesy 
broncho-pueumonia,  one  case  of  tubercle  in  the 
brain,  and  two  cases  of  intestinal  tuberculosis."  In 
all  of  these  the  bacilli  were  present.  They  were 
also  found  in  freshly  extirpated  scrofulous  glands. 
Among  the  lower  animals  they  were  found  in  ten 
cases  of  perkucht,  in  three  cases  of  so-called  bron- 
chiectasis  in  cattle ;  in  three  monkeys,  nine  guinea- 
pigs,  and  seven  rabbits,  which  had  spontaneous 
tuberculosis ;  and  in  one  hundred  and  seventy-two 
guinea-pigs,. thirty-two  rabbits,  and  five  cats,  which 
had  been  inoculated  with  tuberculous  material,  or 
with  pure  cultures  of  the  bacillus. 

The  gelatine  culture-medium  which  had  been 
previously  recommended  by  Koch  was  found  not 
to  be  suitable  for  the  cultivation  of  the  tubercle 
bacillus,  as  the  advantage  of  solidity  is  lost  when 
this  is  heated  to  98°  Fahr.  Jellified  blood-serum, 
prepared  as  directed  on  page  163,  was  found,  how- 
ever, to  fulfil  all  the  required  conditions,  and  was 
used  by  Koch  in  his  culture  experiments.  Portions 
of  tubercles  removed,  with  proper  precautions  to 
prevent  contamination,  from  the  bodies  of  persons 


388  BACTERIA  IN  INFECTIOUS   DISEASES. 

recently  dead  of  tuberculosis,  or  from  the  lower 
animals,  victims  of  spontaneous  or  of  induced  tu- 
berculosis, were  placed  upon  the  surface  of  the 
sterilized  blood-serum,  and  the  vessel  containing  it 
was  kept  in  a  culture-oven  maintained  at  a  tem- 
perature of  40°  C.  (104°  Fahr.).  During  the  first 
week  no  marked  alteration  occurred,  unless  other 
bacteria  had  gained  access  to  the  culture-medium, 
in  which  case  the  experiment  was  a  failure.  About 
the  tenth  day  small  points  and  scales  became  evi- 
dent, which  slowly  spread,  and  upon  microscopical 
examination  proved  to  consist  of  tubercle-bacilli. 
After  fourteen  days  these  bacilli  were  used  to  start 
a  new  culture.  This  was  accomplished  by  break- 
ing up  the  scales  and  transferring  a  minute  quan- 
tity to  the  surface  of  culture  No.  2.  After 
transferring  the  bacilli  in  this  way  to  several 
successive  flasks,  it  was  assumed  that  the  origi- 
nal material  was  excluded,  and  that  a  pure  cul- 
ture had- been  obtained.  Inoculation  of  guinea-pigs 
with  these  pure  cultures  gave  rise  to  tuberculosis 
with  as  great  certainty  as  in  those  experiments  in 
which  tubercular  material  was  used.  In  one  ex- 
periment six  newly  bought  guinea-pigs  were  ob- 
tained. Two  of  these  were  kept  as  temoins,  and 
the  other  four  were  inoculated  with  cultivated 
bacilli  obtained  in  the  first  instance  from  the  lung 
of  a  human  being  who  had  died  of  military  tuber- 
culosis. In  this  instance  five  successive  cultures 
had  been  carried  out,  the  time  required  being  fifty- 
four  days.  One  of  the  inoculated  guinea-pigs  died 


TUBERCULOSIS.  389 

on  the  thirty-second  day,  and  all  the  rest  were 
killed  on  the  thirty-fifth  day.  All  had  extensive 
tuberculosis,  and  the  Bacillus  tuberculosis  was  found 
in  the  tubercles  of  the  lungs,  and  of  various 
organs.  The  two  guinea-pigs  not  inoculated  re- 
mained healthy. 

In  another  experiment  four  rabbits  were  taken. 
Into  the  eye  of  one  pure  blood-serum  was  injected ; 
the  point  of  a  syringe  containing  tubercle  bacilli  in 
blood-serum  was  introduced  into  the  eye  of  a  sec- 
ond. These  were  from  a  series  of  cultures  carried 
out  for  132  days.  In  this  case  the  piston  was  not 
moved ;  but  the  same  material  was  injected  into 
the  eye  of  rabbit  No.  3,  and  of  rabbit  No.  4. 
The  animals  were  killed  on  the  thirtieth  day,  and 
the  following  result  noted  :  Rabbit  No.  1  remained 
healthy ;  rabbit  No.  2  had  typical  tuberculosis  of 
the  iris,  and  the  nearest  lymphatic  glands  were 
swollen  and  infiltrated  with  yellowish  nodules  ; 
but  the  lungs  and  other  organs  were  free  from 
tubercles.  Rabbits  Nos.  3  and  4  had  iritis  and 
tuberculosis  of  the  lungs. 

The  presence  of  Koch's  bacilli  in  tuberculous 
sputum  has  now  been  confirmed  by  numerous  ob- 
servers in  various  parts  of  the  world  ;  and  the 
comparatively  few  failures  to  find  the  bacillus 
which  have  been  reported  by  expert  manipulators 
since  the  method  of  Ehrlich  was  published,  are 
easily  accounted  for  in  other  ways  than  upon  the 
supposition  that  cases  of  tuberculosis  occur  in 
which  no  bacilli  are  found.  Nevertheless  we  must 


390  BACTERIA  IN  INFECTIOUS   DISEASES. 

admit  that  there  are  cases,  recognized  by  expert 
pathologists  as  undoubtedly  tubercular,  in  which 
no  bacilli  can  be  found  in  tubercles  obtained  from 
the  lungs  post  mortem.  Thus  Prudden,  of  New 
York,  while  recording  the  fact  that  he  has,  in  a 
considerable  number  of  cases  of  acute  and  chronic 
phthisis,  found,  almost  invariably,  the  bacillus  of 
Koch  "  in  and  about  all  of  the  cavities,  in  many 
of  the  larger  areas  of  coagulative  necrosis,  and  in 
a  considerable  proportion  of  the  miliary  tuber- 
cles;" yet  reports  two  cases  which  form  an  ex- 
ception to  this  rule.  In  one,  an  abundance  of 
miliary  tubercles  covered  the  lateral  surfaces  of 
both  lobes  of  the  left  lung;  "most  of  these  were 
of  the  usual  giant-celled  and  epithelioid-celled 
type,  with  a  more  or  less  well-marked  reticulum. 
In  none  of  those  examined  was  there  well-marked 
cheesy  degeneration.  Six  hundred  and  ninety-five 
sections,  about  .01  millimeter  in  thickness,  were 
made  from  ninety-nine  different  tubercles  from 
various  parts  of  the  tuberculous  membrane,  and 
stained  in  the  usual  manner  by  Ehrlich's  method 
in  several  different  lots.  In  not  one  of  these  six 
hundred  and  ninety-five  sections  could  a  single 
tubercle  bacillus  be  detected,  although  all  were 
examined  with  the  most  scrupulous  care."  In 
another  case,  "  nine  hundred  and  nine  sections 
from  a  large  number  of  peritoneal  tubercles,  from 
different  parts  of  the  affected  surfaces,  stained  by 
Klirlich's  method,  revealed,  under  the  most  search- 
ing scrutiny,  no  tubercle  bacilli."  In  the  same 


TUBERCULOSIS.  391 

case,  however,  nodules  at  the  apex  of  the  lung, 
and  the  wall  of  a  small  cavity  formed  of  shreds 
of  necrotic  tissue,  of  dense  cheesy  material,  and  in 
the  outermost  layers  of  tubercle  tissue  and  ordi- 
nary dense  connective  tissue,  proved  to  contain 
the  bacillus  in  abundance  in  the  ivatts  and  edges  of 
the  cavity,  and  in  a  few  of  the  dense  areas  of  coagu- 
lation necrosis  in  its  immediate  vicinity.  But  in 
the  diffuse  tubercle  tissue,  in  the  zones  of  simple 
pneumonia  around  the  nodules,  in  the  scattered 
fibrous  tubercles  in  the  lung  and  pleura,  and  in 
the  well-formed  tubercles  in  the  bronchial  glands, 
no  bacilli  could  be  found. 

Koch  has  received  ample  confirmation  as  to  the 
presence  of  the  bacillus  described  by  him,  in 
phthisical  sputum ;  and  its  absence  from  the  spu- 
tum of  patients  suffering  from  other  diseases  seems 
to  be  pretty  well  established,  although  Spina  of 
Vienna  claims  that  other  bacteria  behave  pre- 
cisely towards  staining  agents  as  do  the  bacilli  of 
Koch ;  and,  consequently,  that  the  color-test  can- 
not be  relied  upon  for  distinguishing  this  bacillus 
from  the  ordinary  bacteria  of  putrefaction.  The 
writer's  observations  are  entirely  in  favor  of  the 
statement  of  the  discoverer  of  the  tubercle  bacilli 
as  to  their  peculiar  color  reaction  when  treated  by 
Ehrlich's  method;  but,  like  many  others,  he  has 
not  been  successful  in  demonstrating  them  by  the 
method  first  proposed  by  Koch. 

A  recent  writer1  has  collected  the  statistics,  as 

1  Dr.  Ferguson,  of  Canada.    See  Med.  Record,  New  York,  July  21, 
1883,  p.  77. 


392  BACTERIA  IN  INFECTIOUS  DISEASES. 

\ 

published  in  various  journals,  and  states  that  in 
2,509  cases  reported,  the  bacilli  were  found  in 
2,417-  Koch,  himself,  recognizes,  however,  that 
this  kind  of  evidence  cannot  be  taken  as  proof  of 
the  causal  relation  of  the  bacillus  to  the  morbid 
process  which  results  in  the  formation  of  tubercles 
in  various  parts  of  the  body.  For  it  may  be  that 
the  bacillus  is  present  in  tuberculous  material 
simply  because  this  furnishes  the  pabulum  neces- 
sary for  its  development,  and  is  absent  from  the 
sputum  of  bronchitis,  for  example,  because  this 
does  not  constitute  a  suitable  culture-medium  ;  or 
because,  being  secreted  from  the  surface  of  an 
inflamed  mucous  membrane,  and  quickly  removed 
by  expectoration,  there  is  no  time  for  the  develop, 
ment  of  this  bacillus,  which  Koch  has  shown  re- 
quires at  least  a  week  before  any  evidence  of 
multiplication  is  seen  upon  the  surface  of  sterilized 
blood-serum.  This  time  would,  however,  be  af- 
forded in  the  cheesy  contents  of  a  tubercular 
nodule,  or  in  a  cavity  where  necrotic  products 
were  retained  for  a  considerable  time. 

A  recent  French  writer,  Cochez,  claims  that  the 
sputum  of  phthisical  patients  constitutes  a  favora- 
ble culture-medium  for  the  tubercle  bacillus.  The 
writer,  also,  has  been  inclined  to  believe  that  the 
bacilli  are  more  numerous  in  sputum  which  has 
been  kept  for  a  day  or  two  than  in  the  same 
material  when  first  obtained.  This,  if  true,  is  not 
very  favorable  to  the  view  that  they  are  the  cause 
of  the  morbid  process  which  results  in  the  forma- 


TUBERCULOSIS. 


393 


tion  of  miliary  tubercles,  although  by  no  means 
directly  opposed  to  this  belief. 

An  interesting  communication  relating  to  the 
finding  of  Koch's  bacillus  in  pathological  speci- 
mens which  have  undergone  putrefaction,  or  in 
those  which  have  been  kept  for  some  time  in  pre- 
servative solutions,  has  recently  been  made  by  Vig- 
nal.  This  author  finds  that  "  putrefaction,  even 
very  much  advanced,  does  not  seem  to  interfere 
with  finding  the  tubercle  bacillus.  They  are  also 
found  as  easily  in  pieces  kept  a  long  time  in  90 
per  cent  and  absolute  alcohol,  and  in  Muller's  fluid, 
as  in  recent  preparations." 

The  morphological  characters  of  the  tubercle 
bacillus,  as  found  in  sputum,  are  delineated  in 
Fig.  22.  The  bacilli  are 
found  both  within  and 
without  the  pus-cells, 
and  seem  to  be  espe- 
cially numerous  in  the 
epithelioid  cells.  They 
vary  greatly  in  length, 
and  are  not  infrequently 
curved  or  bent  at  an 
angle  more  or  less  acute. 
Not  infrequently  they 


occur 
little 


in    pairs,    or    in 


groups, 


and 


in 


Fig  22. 

Koch's  Bacillus  tuberculosis,  in  sputum; 
stained  by  Ehrlich's  method.  X  1000 
(G.  M.  8.,  del.) 


some  cases  it  is  apparent  that  they  contain  endo- 
genous spores,  or  that  they  are  made  up  of  a  chain 
of  oval  elements. 


PLATE   IX. 

Bacillus  Tuberculosis. 

FIG.  1. —  Section  of  miliary  tubercle  of  lung;  the  tubercle 
bacilli  stained  blue,  and  the  cell  nuclei  brown.  X  700.  Koch 
(from  Mitth.  a.  d.  k.  Gsndhtsamte  Vol.  ii.  Taf.  I.  Fig.  2). 

FIG.  2.  —  Colonies  of  tubercle  bacilli  from  surface  culture. 
X  700.  Koch  (op.  cit.  Taf.  IX.,  Fig.  44). 

FIG.  3.  —  Giant-cell  containing  tubercle  bacilli,  from  a  caseous 
bronchial  gland  of  a  case  of  miliary  tuberculosis.  X  700.  Koch 
(op.  cit.  Taf.  XI.  Fig.  9). 


PLA  - 


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Fis  3. 


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TUBERCULOSIS.  397 

In  the  first  edition  of  this  work  the  writer  gave 
a  summary  of  results  obtained  in  his  own  experi- 
ments, made  soon  after  the  announcement  of  Koch's 
discovery.  This  has  been  omitted  from  the  pres- 
ent edition  to  make  room  for  Plate  IX,  which  is 
an  accurate  reproduction  of  the  selected  figures, 
copied  from  Vol.  II.  of  the  "  Mittheilungen." 

In  the  experiments  referred  to,  several  rabbits 
and  two  guinea-pigs  were  successfully  inoculated 
with  tuberculous  sputum,  and  an  attempt  was 
made  to  cultivate  the  bacillus,  but  without  success. 
Failure  was  probably  due  to  the  fact  that,  not 
having  a  supply  of  gas  at  the  military  post  where 
the  experiments  were  conducted,  it  was  found 
impossible  to  regulate  the  temperature  of  the 
culture-oven  to  as  nice  a  point  as  appears  to  be 
necessary.  "  In  the  animals  successfully  inocu- 
lated the  enlarged  tuberculous  lymphatic  glands 
in  the  vicinity  of  the  point  of  inoculation,  and 
tubercle  nodules  in  the  lungs  and  elsewhere,  usually 
contained  the  bacillus  of  Koch.  But  this  was  not 
invariably  the  case."  The  writer  is  at  present 
inclined  to  believe  that  a  more  protracted  search 
might  have  demonstrated  their  presence  in  every 
case.  Some  recent  experiments  made  in  Balti- 
more (not  yet  published),  and  a  careful  considera- 
tion of  the  experimental  evidence  as  given  by 
Koch  in  his  elaborate  memoir  in  the  second  volume 
of  the  "  Report  of  the  Imperial  Board  of  Health," 
have  removed  the  last  remnant  of  scepticism  from 
the  writer's  mind ;  and  to-day  he  considers  it 
established  that  tuberculosis  is  an  infectious  dis- 


398  BACTERIA  IN  INFECTIOUS  DISEASES. 

ease,  in  which  the  essential  etiological  agent  is  the 
bacillus  discovered  by  Koch.  The  possibility  that 
the  special  pathogenic  power  of  this  bacillus  is  an 
acquired  rather  than  an  essential  physiological 
character,  depending  upon  the  fact  that  it  has 
been  bred  for  many  successive  generations  in  a 
tuberculous  soil,  and  that  it  is  in  truth  a  pathogenic 
variety  of  a  common  and  widely  distributed  species, 
seems  to  be  worthy  of  further  consideration. 

Dr.  Watson  Cheyne  of  London,  a  very  compe- 
tent, witness  in  a  case  of  this  kind,  has  repeated 
Koch's  experiments,  and  fully  confirms  him  in  all 
essential  particulars. 

This  author  paid  a  visit  to  Toussaint  and  to 
Koch  for  the  purpose  of  making  himself  familiar 
with  their  methods.  Upon  his  return  to  England, 
a  series  of  experiments  was  made,  with  the  results 
reported  below. 

The  experiments  were  made  under  the  most 
favorable  hygienic  conditions,  and  all  possible  pre- 
cautions were  taken  as  regards  disinfection  of 
instruments  and  the  complete  isolation  of  the  ani- 
mals used.  Twenty-five  animals,  inoculated  with 
non-tubercular  material  in  various  ways,  failed  to 
become  tuberculous.  In  six  of  these,  setons  were 
introduced  subcutaneously ;  in  ten,  vaccine  lymph 
was  employed  ;  in  three,  pyoemic  pus  was  injected  ; 
and  in  six,  various  materials  were  introduced  into 
the  abdominal  cavity  (cork,  tubercle  hardened  in 
alcohol,  worsted  thread).  Cheyne  believes  that 
in  similar  experiments 'made  by  other  observers,  in 
which  a  positive  result  has  been  reported,  the 


TUBERCULOSIS.  399 

tubercle  bacilli  have  always  been  introduced  acci- 
dentally, with  the  innocuous  material  to  which  the 
result  has  commonly  been  ascribed. 

Toussaint,  who  has  ascribed  the  disease  to  a 
micrococcus,  furnished  our  author  cultures  of  this 
micrococcus  obtained  by  inoculating  blood-serum 
or  rabbit  bouillon  with  the  blood  of  a  tuberculous 
animal.  This  material  was  injected  into  three 
rabbits,  two  guinea-pigs,  one  cat,  and  one  mouse. 
In  no  instance  did  tuberculosis  ensue.  The  injec- 
tions in  Cheyne's  experiments  were  made,  when- 
ever practicable,  into  the  anterior  chamber  of  the 
eye,  with  a  syringe  which  had  been  purified  by 
heat.  Cultivations  of  the  micrococci  obtained  from 
Toussaint  were  also  made  and  injected  into  nine 
rabbits  and  three  guinea-pigs,  with  a  negative 
result.  The  tuberculous  organs  of  animals  ex- 
perimented upon  by  Toussaint  were  examined  by 
Cheyne,  who  found  in  them,  often  in  large  num- 
bers, the  bacillus  of  Koch,  but  no  micrococci ; 
although  some  of  these  animals  had  developed 
tuberculosis  as  a  result  of  inoculation  by  Toussaint, 
with  cultures  of  the  micrococcus  described  by  him. 
This  result  is  ascribed  to  accidental  inoculation 
with  the  spores  of  the  tubercle  bacillus,  which 
Cheyne  shows  would  not  be  destroyed  by  the 
method  of  disinfection  upon  which  Toussaint  has 
relied,  namely,  the  cleansing  of  his  syringe  with 
an  aqueous  solution  of  carbolic  acid. 

Twelve  rabbits  were  also  inoculated  with  culti- 
vations of  the  tubercle  bacillus  obtained  from  Koch. 


400  BACTERIA  IN  INFECTIOUS   DISEASES. 

"All  of  these  became  tuberculous,  and  that  more  rapidly 
than  after  inoculation  with  tuberculous  material.  The 
tubercles  produced  in  these  cases  were  infec- 
tive and  produced  tuberculosis  in  other  animals. 
On  examination  of  tuberculous  material,  Koch's 
bacilli  are  always  found,  though  in  varying  num- 
bers. They  are  most  numerous  in  bovine  tuber- 
culosis, and  least  numerous  in  human  tuberculosis. 
About  eighty  organs  of  tuberculous  animals  and 
thirty-six  cases  of  human  tuberculosis  were  ex- 
amined, and  in  all  of  these,  without  exception, 
tubercle  bacilli  were  found."  1 

TYPHOID  FEVER. —  The  established  facts  relating 
to  the  origin  of  isolated  cases  and  local  epidemics 
of  typhoid  fever  all  point  to  the  existence  of  a 
contagium  vivum  capable  of  self-multiplication  ex- 
ternal to  the  human  body,  and  which  commonly 
gains  access  to  the  intestinal  canal  of  those  at- 
tacked with  the  disease  through  the  ingestion  of 
infected  material,  and  especially  of  unboiled  fluids, 
particularly  of  water  and  milk.  It  is  generally 
recognized  that  the  infective  agent  is  contained  in 
the  stools  of  typhoid  patients,  and  that  it  may  in- 
crease indefinitely  in  a  proper  pabulum,  and  under 
favorable  conditions  as  to  temperature,  when  these 
stools  are  carelessly  mixed  with  organic  material 
in  cess-pools,  privy-vaults,  etc. 

There  is  nothing  in  the  clinical  history  of  the 

1  Quoted  from  abstract  in  "  Braithwaite's  Retrospect,"  Part  LXXX  VII. 
p.  73. 


TYPHOID  FEVER.  401 

disease  under  consideration,  or  in  known  facts 
relating  to  its  epidemic  extension,  to  indicate  that 
the  typhoid  germ  multiplies  in  the  blood  of  those 
attacked  with  the  disease ;  and  the  negative  results 
which  have,  for  the  most  part,  been  reported  by 
those  who  have  sought  it  in  this  fluid,  correspond 
with  what  might  a  priori  have  been  expected. 

Meyer,  however,  has  reported  the  finding  of 
bacilli  in  great  numbers  in  the  blood  of  a  case  of 
typhoid  which  resulted  fatally  from  congestion 
of  the  lungs  and  kidneys,  at  the  end  of  two  days. 
But  it  may  be  questioned  whether  the  pathological 
appearances  would  be  sufficiently  marked  at  so 
early  a  date  to  establish  the  diagnosis ;  and,  in 
any  event,  the  finding  of  micro-organisms  in  blood 
obtained  post  mortem  has  little  import,  unless  the 
same  organisms  were  found  in  this  fluid  before 
death.  Almquist  reports  that  he  has  occasionally 
found  groups  of  microbes  in  the  blood  in  small 
numbers.  These  were  short  rods,  and  were  most 
abundant  during  the  second  or  third  week  of  sick- 
ness. In  this,  as  in  other  diseases,  we  must  bear 
in  mind  the  possibility  that  a  septic  complication 
may  be  attended  by  invasion  of  the  blood  by  micro- 
organisms not  bearing  any  direct  relation  to  the 
typhoid  process;  and  also  that  non-pathogenic 
bacteria  may  possibly  invade  the  circulating  fluid 
when  the  vital  powers  are  at  a  low  ebb. 

Maragliano  found  in  blood  drawn  from  the  spleen 
by  means  of  a  hypodermic  syringe,  motile  and 
motionless  micrococci,  and  also  a  small  number  of 

26 


402  BACTERIA  IN  INFECTIOUS  DISEASES. 

rods  like  those  described  by  Eberth.  Letzerich 
also  claims  to  have  recognized  the  rnicrococci 
which  he  supposes  to  be  the  specific  germs  of 
typhoid  in  the  blood  and  in  the  sputum.  Moxon, 
iu  a  recent  paper  "  On  our  Present  Knowledge  of 
Fever/'  remarks  as  follows :  — 

"  You  must  not  suppose  that  one  has  only  to  get  a 
microscope  and  a  slide  and  put  a  little  fever  blood  under 
it  to  find  it  full  of  germs.  No  ;  try  in  any  of  our  cases 
of  typhoid  in  the  wards,  and  you  will  find  these  germs 
by  no  means  very  easily  discovered  or  obvious  things. 
At  the  outset  of  such  an  inquiry,  you  must  take  notice 
that  the  blood-serum  is  often  crowded  with  minute  par- 
ticles, which  must  not  be  confounded  with  bacteria,  and 
which  exist,  often  to  a  large  extent,  in  the  blood  of 
healthy  persons.  During  last  winter's  clinical  session, 
some  of  my  most  acute  and  intelligent  -friends  searched 
carefully  for  germs  in  the  blood  of  several  severe  typhoid 
cases.  The  result  was  that  one  bacterium  was  seen, 
only  one,  but  I  was  told  it  was  a  very  active  one.  When 
I  say  that  Mr.  Booth  saw  it,  you  will  know  it  was  well 
seen,  for  we  all  regard  Mr.  Booth  as  one  of  the  very 
ablest  and  very  best  students  at  Guy's;  but  perhaps 
the  main  fact  was  that  all  were  quite  sure  that  there 
was  only  one  bacterium."  l 

The  attempts  which  have  been  made  to  produce 
typhoid  fever  in  the  lower  animals  have  not  given 
any  results  of  a  sufficiently  definite  character  to 
make  it  possible  to  study  the  etiology  of  this  dis- 
ease by  the  method  of  inoculation  with  pure-cul- 
tures of  suspected  organisms.  And  for  the  present 

1  Lancet,  December  9,  1882,  p.  974. 


TYPHOID  FEVER.  403 

the  evidence  in  favor  of  the  various  organisms 
which  have  been  supposed  by  different  observers 
to  be  the  veritable  typhoid  germs,  is  mainly  that 
obtained  by  the  microscopical  examination  of  the 
tissues  involved  in  the  local  lesions  which  character- 
ize the  disease.  When  we  consider  that  the  healthy 
intestine  is  the  usual  habitat  of  a  large  number  of 
species  of  bacterial  organisms,  and  that  some  of 
these  promptly  invade  necrotic  tissues,  —  and  pos- 
sibly living  tissues  having  a  low  grade  of  vitality, 
or  which  are  deprived  of  their  normal  relations  by 
inflammatory  exudates  which  furnish  a  suitable 
pabulum  for  parasitic  micro-organisms,  —  we  shall 
appreciate  the  difficulty  of  deciding  whether  necro- 
sis of  invaded  tissues  is  a  result  of  the  parasitic 
invasion,  or  whether  the  mycosis  has  been  secondary 
to  and  independent  of  the  morbid  process. 

Eberth  seems  to  have  very  fully  appreciated 
these  difficulties,  and  it  is  doubtful  whether  any 
more  satisfactory  evidence  can  be  obtained  than 
that  which  he  has  offered  in  favor  of  the  view  that 
the  bacillus  described  by  him  is  the  much  sought 
typhoid  germ,  unless  future  experiments  upon 
the  lower  animals  give  more  definite  results  than 
have  been  heretofore  reported.  As  pointed  out  by 
Eberth,  the  results  reported  by  Walder  in  his  experi- 
ments upon  calves,  dogs,  cats,  rabbits,  and  chickens, 
are  entirely  unreliable,  as  no  account  seems  to 
have  been  made  of  septicsemic  complications  which 
could  scarcely  fail  to  occur  from  the  ingestion  of 
putrid  material, —  blood,  typhoid  stools,  etc.,  used 


404  BACTERIA  IN  INFECTIOUS  DISEASES. 

in  many  of  his  experiments.  Letzerich  also  seems 
to  have  been  ignorant  of  the  fact  that  the  sputum 
of  healthy  persons  produces  septicaemia  in  rabbits, 
and  his  inference  that  rabbits  inoculated  with  the 
sputum  of  a  fever  patient  suffered  an  attack  of 
genuine  typhoid,  is  probably  as  wide  of  the  mark  as 
was  Pasteur's  with  reference  to  the  u  new  disease  " 
described  by  him  as  resulting  from  inoculating 
rabbits  with  the  saliva  of  a  child  dead  of  hydro- 
phobia. One  of  Letzerich's  rabbits  died  at  the 
end  of  five  days,  and  one  was  killed  at  the  end  of 
twelve  days.  Micrococci  and  rods  were  found  in 
the  spleen,  in  the  veins,  and  in  the  follicles  of  the 
intestine,  but  the  evidence  presented  in  favor,  of 
the  view  that  these  animals  had  typhoid  fever  is 
entirely  unsatisfactory. 

Brantlecht  produced  in  young  rabbits  most  of 
the  typhoid  symptoms  by  the  subcutaneous  injec- 
tion of  culture-liquids;  but  he  obtained  the  same 
results  with  bacilli  found  during  the  summer  months 
in  the  water  of  stagnant  ponds  (Cameron).  Chom- 
jakoff,  a  pupil  of  Klebs,  injected  typhoid  ba- 
cilli (?)  into  the  peritoneum  of  rabbits.  The 
animals  immediately  exhibited  an  elevation  of 
temperature,  which  attained  its  maximum  on  the 
third  day.  They  all  died  on  the  third  or  fourth 
day,  in  two  instances  with  diarrhoea.  The  lesions 
were,  redness  and  tumefaction  of  Peyer's  glands, 
increase  in  volume  of  the  spleen,  cellular  infiltra- 
tion of  the  intestinal  tissues.  The  presence  of 
micrococci  was  doubtful,  but  the  peritonitis  was  in 


TYPHOID  FEVER  405 

inverse  ratio  to  the  cultivation.  The  evident  criti- 
cism in  experiments  of  this  kind  is  that  the  results 
are  necessarily  complicated  by  the  peritonitis  re- 
sulting from  the  introduction  of  micro-organisms 
into  the  cavity  of  the  abdomen ;  that  the  symp- 
toms follow  the  injection  immediately,  while  in 
man  there  is  a  certain  period  of  incubation  ;  and 
that  the  death  at  the  end  of  four  days  of  an  animal 
very  susceptible  to  various  forms  of  septicsemia, 
but  which,  so  far  as  we  know,  never  contracts 
typhoid  fever  spontaneously,  can  hardly  be  taken 
as  evidence  that  the  micro-organisms  injected  into 
its  peritoneal  cavity  were  veritable  typhoid  germs. 
Indeed,  we  cannot  help  suspecting  that  other  in- 
vestigators operating  with  micro-organisms  from 
other  sources  would  have  found  in  the  symptoms 
and  pathological  lesions  evidence  of  yellow  fever, 
or  of  continued  malarial  fever,  or  possibly  of  scarlet 
fever,  without  the  rash  ;  for  the  absence  of  the 
characteristic  rash  could  be  easily  explained  by 
the  fact  that  the  integument  is  thickly  covered 
from  sight  by  a  heavy  growth  of  hair.  Klebs 
also  introduced  cultivated  typhoid  organisms  into 
the  cavity  of  the  abdomen  in  eleven  rabbits.  In 
one  only  death  occurred  at  the  end  of  four  days ; 
and  upon  this  slim  foundation  the  inference  was 
made  that  the  organisms  used  in  the  experiment 
were  veritable  typhoid  germs. 

44  Tigri  first  found  bacteria  in  the  blood  of  a  man  dead 
with  typhoid  fever.  These  organisms  were  also  found 
by  Signoi  (1863)  and  Megrim  (1866)  in  the  blood  of 


406 


BACTERIA  IN  INFECTIOUS  DISEASES. 


horses  attacked  by  a  disease  called  by  the  veterinarians 
typhoid  fever.  This  blood,  by  inoculation,  produced  the 
death  of  some  rabbits,  with  the  same  alterations  in  the 
blood. 

"  Coze  and  Feltz  (1866),  having  inoculated  some  rab- 
bits with  the  blood  of  typhoid  fever,  have  produced 
results  which  they  consider  analogous,  and  as  accom- 
panied by  the  same  pathological  localizations  in  the 
glands  of  Peyer.  The  blood  of  an  injected  rabbit  may 
be  used  upon  a  second  rabbit,  with  positive  results,  as 
in  variola  and  scarlatina. 

"  The  species  of  Bacterium  which  is  found  in  this  case 
recalls  the  Bacterium  catenula,  but  its  dimensions  are 
less."  (Magnin.) 

The  presence  of  micro-organisms  in  the  local 
lesions  of  typhoid  fever  has  been  verified  by 

numerous  observ- 
ers, and,  as  already 
remarked,  was  a 
priori  to  have  been 
expected.  The  sta- 
tistics of  these  ob- 
servations, there- 
fore, which  Eberth 


has 


given    us, 


al- 


though interesting, 
have  comparatively 
little  value.  Ac- 
cording to  this  au- 
thor, Von  Reck- 
lingliausrn  first 
described  micro-organisms  in  abdominal  typhus. 


Fig.  23. 

Vertical  section  of  intestine,  typhoid  feyer,  showing 
the  border  of  the  submucoea  infiltrated  by  ha- 
cilll.  Hartnack  im.  No.  9,  Ocular  2  (Klebs). 


TYPHOID  FEVER. 


407 


Fig.  24. 


These  were  found  in  the  typhoid  ulcers,  and  con- 
sisted of  masses  of  micrococci.  Klein  also  found 
groups  of  micro- 
cocci  in  the  mucous 
membrane,  in  the 
lymph  follicles,  and 
in  the  spleen.  Fische 
found  colonies  of 
micrococci  in  the 
spleen  and  in  the 
lymphatic  glands  in 
fifteen  outof  twenty- 
nine  cases  exam- 
ined. The  positive 
results  were  mostly 

From  a  fresh  section  of  typhoid  intestine  ;  treated 

Obtained     in      recent  withglacial  acetic  acid  and  glycerine  mixture. 

n  ,  i  Sieberfs  im.  No.  7,  Ocular  3   Klebs). 

cases;  some  of  these, 

however,  gave  a  negative  result.  Klebs  found 
organisms  —  micrococci  or  bacilli  —  in  twenty-four 
cases  examined  by  him.  Koch  found  bacteria  in 
half  the  cases  which  he  examined ;  Meyer  in 
eighteen  out  of  twenty-four;  and  Eberth  in 
eighteen  out  of  forty.  Eberth  remarks  that  the 
result  would  probably  have  been  more  favorable 
but  for  the  fact  that  the  organism  in  many  cases 
seems  to  have  been  destroyed  in  the  tissues.  In 
the  negative  cases  the  height  of  the  fever  was 
already  past.  The  bacilli  are  said  to  be  most  nu- 
merous during  the  first  twelve  or  fourteen  days  of 
sickness,  less  numerous  at  the  end  of  the  third 
week,  and  they  were  seldom  met  with  in  the  fifth 


408  BACTERIA  IN  INFECTIOUS  DISEASES. 

or  sixth  week;  if  found  then  they  present   evi- 
dence of  having  undergone  retrograde  change. 

The  typhoid  germ  of  Letzerich  is  a  rnicrococcus, 
isolated,  in  colonies,  or  in  chains,  very  dissimilar 
to  those  of  diphtheria  and  of  infectious  pneumonia, 
but  which  by  cultivation  may  reach  twice  or  three 
times  the  size  of  the  micrococci  of  the  last  men- 
tioned diseases. 

Klebs  describes  his  Bacillus  typhosus  as  large- 
sized  filaments  of  50  p  in  length  and  0.2  ^  in 

breadth,  without 
segments  or  rami- 
fications. When 
the  spores  make 
their  appearance 
the  filaments  may 
reach  0.5  p.  in 
breadth.  The 
spores  are  ar- 
ranged in  a  line, 
and  very  close 
together.  Before 

Fig.  26.  «  , 

they    are    formed, 

Section  of  typhoid  lung ;  fresh;   treated  with  mixture  . 

of  glycerine  and  glacial   acetic    acid.      Siebert's     tll6        baCllll        CXlSt 

as  short  rods  (see 
Figs.  23,  24,  and  25). 

The  morphological  characters  of  the  bacillus  of 
Eberth  are  shown  in  Fig.  26,  which  is  copied  from 
his  paper,  referred  to  in  bibliography. 

When  these  bacilli  are  present  in  great  numbers 
they  have  the  appearance  of  masses  of  micrococci. 


TYPHOID  FEVER. 


409 


Fig.  26. 

Typhoid  bacilli  from  a  lymphatic 
gland.  Hartnack  No.  12,  Ocu- 
lar 3.  (From  Eberth,  "Der 
Typhus-bacillus  und  die  intes- 
tinale  Infection.") 


But  when  isolated  from  these 
masses  they  are  recognized 
as  short  thick  rods  having 
rounded  ends.  With  high 
powers  many  of  the  bacilli 
may  be  seen  to  contain  two 
or  three  granules,  which  are 
probably  spores.  The  rods 
are  sometimes  found,  in  the 
juice  scraped  from  the  freshly 
cut  surface  of  a  diseased 
lymphatic  gland,  in  chains 
of  two  or  three  elements.  The  characters  by  which 
these  bacilli  are  recognized  are  the  rounded  ex- 
tremities, and  the  fact  that  they  are  not  so  deeply 
stained  by  the  aniline  dyes  as  are  the  putrefaction 
bacteria  often  found  in  the  same  preparation.  In 
addition  to  these  bacilli,  Eberth  recognizes  at  least 
seven  micro-organisms  which  he  has  met  with  in 
his  microscopical  studies,  and  which  may  be  asso- 
ciated with  them.  But  the  bacillus  with  rounded 
ends  is  said  to  be  peculiar  to  typhoid,  and  has  not 
be'en  found  in  a  single  instance  out  of  twenty-four 
cases  of  intestinal  disease  of  a  different  character, 
—  e.  g.,  tuberculosis  of  the  bowels,  —  in  which  he 
has  made  a  careful  examination  by  the  same  meth- 
ods. Similar  negative  results  were  obtained  by 
Mayer  in  six  cases  of  dysentery  and  other  diseases 
of  the  bowels.  Koch  is  of  the  opinion  that  the 
bacillus  of  Eberth  is  the  only  one  which  has  a 
specific  relation  to  the  disease.  According  to  this 


410  BACTERIA  IN  INFECTIOUS  DISEASES. 

observer  Klebs's  elongated  bacilli  belong  to  the 
putrid  parts,  and  only  invade  the  necrotic  tissues 
which  have  succumbed  to  the  attack  of  the  spe- 
cific typhoid  bacillus. 

Eberth  also  describes  a  small  and  comparatively 
long  bacillus,  which  no  doubt  corresponds  with  that 
of  Klebs,  which  is  found  isolated  and  in  groups  in 
the  superficial  layers  of  the  necrotic  tissues.  "Their 
appearance  and  color-reaction  show  them  to  be 
ordinary  putrefaction  bacteria  of  the  intestinal 
contents.'*  As  evidence  of  the  number  of  bac- 
terial organisms  constantly  present  in  the  intesti- 
nal canal  of  healthy  persons,  the  reader  is  referred 
to  the  photo-micrograph  in  Plate  VII.,  Fig.  4.  This, 
however,  by  no  means  shows  all  the  forms  which 
may  be  found  at  different  times  in  the  discharges 
of  persons  in  perfect  health.  (See  also  Plate  XIII., 
illustrating  the  writer's  paper  on  "  Bacteria  in 
Healthy  Individuals  "  in  Vol.  II,  No.  2,  of  "  Stud- 
ies from  the  Biological  Laboratory "  Johns  Hop- 
kins University.) 

Coates,  of  Glasgow,  confirms  Eberth  as  to  the 
presence  of  the  bacillus  described  by  him  in  a  dis- 
eased lymphatic  gland  removed  from  a  case  of 
typhoid  fatal  on  the  ninth  day.  Crook  has  also 
found  the  bacillus  in  a  case  treated  in  the  Fever 
Hospital  of  Leeds. 

The  writer  would  simply  remark,  in  regard  to 
this  bacillus,  that  the  distinctive  character  upon 
which  Eberth  chiefly  relies,  seems  hardly  sufficient 
to  establish  it  as  a  distinct  species,  when  we  com- 


ULCER ATIVE    ENDOCARDITIS —  VARIOLA.         411 

pare  his  figure  (Fig.  26)  with  that  of  Cheyne 
(Fig.  28),  and  with  my  photo-micrograph,  Fig.  1, 
Plate  VIII.  Certainly  the  rounded  ends  of  this 
typhoid  bacillus  are  not  peculiar  to  it.  (The 
photo-micrographs  referred  to  have  been  omitted 
from  this  edition.) 

ULCERATIVE  ENDOCARDITIS.  —  "  In  this  affection,  it 
is  well  settled  to-day  that  the  cardiac  walls  and,  above 
all,  the  valves,  are  covered  with  parasitic  masses.  Some 
think  that  the  malady  is  due  to  the  introduction  of 
these  parasites  into  the  interior  of  the  tissues  ;  others, 
on  the  contrary,  like  Hiller,  deny  that  the  bacteria  bear 
any  casual  relation  with  the  lesions  of  ulcerative  endo- 
carditis." (Magnin.) 

VARIOLA.  —  "  The  partisans  of  the  parasitic  nature  of 
variola  may  be  divided  into  two  groups :  1.  Those  who, 
with  Coze  and  Feltz,  attribute  the  virulence  to  a  Bac- 
terium ;  2.  Those  who,  with  Luginbiihl  and  Weigert, 
attribute  it  to  a  Micrococcus.  Coze  and  Feltz  have  in- 
deed discovered  bacteria  in  the  blood  of  variola,  and 
this  blood  injected  into  the  veins  of  a  rabbit  has  given 
it  a  mortal  malady,  which  these  observers  consider  vari- 
ola. But  Chauveau  has  shown  that  the  affection  which 
proved  fatal  to  the  subjects  of  the  experiment  was  not 
and  could  not  be  variola.  Another  objection  is  that 
bacteria  are  not  found  in  all  those  who  suffer  from 
variola.  However,  Coze  and  Feltz  and  Baudouin  affirm 
that  there  are  in  variolous  blood  numerous  rods,  of 
which  the  appearance  is  similar  to  that  of  Bacterium 
bacillus  and  Bacterium  termo  of  Miiller.  These  ele- 
ments do  not  at  all  resemble  those  found  in  other 
infections,  and  when  inoculated  possess  the  power  of 
reproducing  variola. 

"As  to  the  Micrococcus  of  variola,  they  have  been 


412  BACTERIA  IN  INFECTIOUS  DISEASES. 

studied  by  Luginbiihl,  Weigert,  Hallier,  and  Cuhn. 
These  micro-organisms  possess  the  characters  of  all  the 
spherical  bacteria,  and  are  found  in  the  variolous  pus- 
tules, the  rete  Malpiyldi,  the  liver,  the  spleen,  the  kid- 
neys, and  the  lymphatic  ganglia.  We  can  only  insist 
upon  the  fact  of  the  concomitance  of  the  variola  and 
the  presence  of  micrococci,  since  experiment  cannot  be 
resorted  to  in  this  disease,  of  which  the  complete  evolu- 
tion occurs  only  in  man.  We  also  find  in  vaccine  lymph 
micrococci  analogous,  in  every  point  of  view,  to  those  of 
variola.  Cohn  considers  them  both,  not  as  distinct 
species,  but  as  two  races  of  the  same  species,  —  the 
Micrococcus  vaccince."  (Magnin.) 

"M.  Straus  presented  to  a  recent  meeting  of  the 
Socie'te'  de  Biologic  at  Paris  a  series  of  microscopical 
preparations  of  the  vaccinal  pustule  of  the  calf,  at  dif- 
ferent stages  of  its  progress,  in  which  the  presence  of 
the  special  micrococcus  could  readily  be  observed.  The 
method  of  preparation  adopted  was  to  place  the  excised 
fragments  of  skin  in  absolute  alcohol,  to  cut  sections, 
and  stain  by  Weigert's  method  (methylamine  violet), 
and  then  discoloring  them  until  only  the  nuclei,  the 
bacteria,  and  micrococci  remain  visible.  Under  a  high 
power,  the  latter  were  visible  as  extremely  minute 
points,  tinted  blue,  about  a  thousandth  part  of  a  milli- 
meter in  diameter,  and  grouped  in  colonies.  They  were 
seen  in  the  borders  of  the  inoculation  wound,  and  in 
the  Malpighian  layer,  and  subsequently  could  be  traced 
passing  into  the  subjacent  cutis,  especially  in  the  lym- 
phatic spaces.  The  multiplication  and  extension  of  the 
organism  seemed  to  coincide  closely  with  the  develop- 
ment of  the  pustule."  l 

Dr.  Wolff  claims  to  have  successfully  cultivated 

1  J.  Koy.  Microscopical  Soc ,  Oct.  1882,  p.  661. 


VARIOLA  OF  PIGEONS.  413 

the  micrococcus  vaccince  through  fifteen  successive 
generations.1  If  this  is  true  he  will  be  able  to 
claim  the  prize  offered  by  the  Grocers'  Company 
of  London :  — 

44  The  subject  of  the  Grocers'  Company's  first  discov- 
ery prize  of  X  1,000  for  original  research  in  connection 
with  sanitary  science  is  4  A  method  by  which  the  vac- 
cine contagion  may  be  cultivated  apart  from  the  animal 
body,  in  some  medium  or  media  not  otherwise  zymotic'; 
the  method  to  be  such  that  the  contagium  may  by  means 
of  it  be  multiplied  to  an  indefinite  extent  in  successive 
generations,  and  that  the  product  after  any  number  of 
such  generations  shall  (so  far  as  can  within  the  time  be 
tested)  prove  itself  of  identical  potency  with  standard 
vaccine  lymph.'  The  prize  is  open  to  universal  compe- 
tition, British  and  foreign.  Competitors  for  the  prize 
must  submit  their  respective  treatises  on  or  before  the 
31st  of  December,  1886,  and  the  award  will  be  made 
as  soon  afterwards  as  the  circumstances  of  the  compe- 
tition shall  permit,  but  not  later  than  the  month  of 
May,  1887.  All  communications  on  the  subject  must 
be  addressed  to  the  clerk  of  the  Grocers'  Company, 
London,  from  whom  circulars  giving  the  conditions  can 
be  obtained." 

VARIOLA  OF  PIGEONS.  —  In  a  communication 
to  the  French  Academy,  presented  by  Vulpian, 
M.  Jolyet  gives  an  account  of  an  experimental  re- 
search, made  in  collaboration  with  MM.  Delage 
and  Lagrolet,  relating  to  the  etiology  of  the  dis- 
ease known  as  variola  of  the  pigeon  or  picote.  He 
says :  — 

1  Berlin  Klin.  Wochenschrift,  Jan.  22,  1883. 


414  BACTERIA  IN  INFECTIOUS   DISEASES. 

"  Microscopical  examination  of  the  blood  of  pigeons 
attacked  with  variola  shows  that  this  liquid  contains  an 
infinite  number  of  living  microbes.  This  alteration 
is  constant,  and  is  true  in  the  case  of  pigeons  attacked 
spontaneously,  as  well  as  of  those  which  have  been  sub- 
jected to  experimental  inoculation. 

"  Upon  studying  the  development  of  the  microbes  in 
the  blood,  the  following  facts  worthy  of  note  may  be 
observed.  The  first  important  point  consists  in  the 
progressive  development  of  the  organisms  in  correspond- 
ence with  the  progress  of  the  disease.  Their  appear- 
ance in  the  blood  always  precedes  the  appearance  of 
morbid  phenomena.  This  fact  is  especially  easy  of 
verification  in  pigeons  which  have  been  inoculated, 
by  means  of  a  vaccination  needle,  either  with  the  blood 
of  a  sick  animal,  or  with  the  liquid  contained  in  the 
pustules. 

"  If  after  inoculation  we  examine  each  day  the  blood 
of  pigeons,  we  shall  find  that  during  the  first,  second, 
and  often  the  third  day,  it  presents  nothing  abnormal  in 
its  appearance  ;  however,  towards  the  end  of  the  third 
day  an  attentive  examination  will  already  demonstrate 
the  presence  of  the  microbes  in  the  blood  ;  the  following 
days  the  parasite  increases  rapidly,  and  when  the  pigeon 
presents  manifest  symptoms  of  illness,  a  microscopic 
preparation  of  the  blood  offers  myriads  of  microbes  in 
movement. 

"  This  period,  from  the  time  of  inoculation  until  the 
development  of  morbid  phenomena,  corresponds  with 
the  period  of  incubation  so  characteristic  of  other  viru- 
lent and  contagious  maladies.  The  greatest  number  of 
parasitic  organisms  are  found  in  the  blood  just  before 
the  eruption  appears.  Subsequently  they  gradually 
decrease  in  number. 

"The  pus  of  the  pustules  contains  the  characteristic 


WHOOPING   COUGH.  415 

microbes  in  abundance,  and  produces  the  disease  when 
inoculated  into  healthy  pigeons.  .  .  . 

44  In  a  certain  number  of  pigeons  the  cutaneous  erup- 
tion is  wanting,  and  in  this  case  the  autopsy  reveals  a 
veritable  intestinal  pustulation. 

44  The  microbes  from  the  pustules  or  from  the  blood, 
cultivated  in  pigeon  bouillon,  have  furnished  successive 
culture-liquids  which,  when  inoculated,  reproduce  the 
disease. 

44  But  it  is  the  blood  (in  vitro)  and  the  lymph  which 
are  the  best  culture  media  for  the  microbes  of  variola, 
either  of  man  or  of  the  lower  animals.  And  neverthe- 
less, if  we  examine  the  blood  of  subjects  attacked  with 
variola  (man,  the  pig)  we  find  that  it  contains  but  few 
microbes,  so  that  it  is  difficult  to  suppose  that  these  or- 
ganisms are  the  first  cause  of  the  malady.  So  also  in 
charbon,  in  many  animals  but  few  bacteries  are  found  in 
the  blood  at  the  moment  of  death.  This  is  because, 
in  the  living  animal,  the  most  favorable  medium  for 
the  development  of  these  infectious  organisms  is  the 
lymph.  Numerous  observations  enable  us  to  affirm 
this  fact.  .  .  . 

44  In  conclusion  we  will  say  that  if  the  microbes  in  the 
course  of  an  infectious  malady  do  not  multiply  in  the 
blood  in  circulation,  they  are  susceptible  of  multiplica- 
tion in  the  blood  in  repose,  drawn  directly  from  an 
artery  into  Pasteur's  flasks  —  sterilized,  and  that  they 
retain  their  specific  qualities." 

WHOOPING  COUGH.  — 4t  Poulet,  in  1867,  found  certain 
bacteria  of  a  peculiar  kind  in  the  sputa  of  patients  affected 
with  pertussis  ;  Letzerich  commenced  a  series  of  investi- 
gations a  few  years  later.  The  latter  found  constantly 
present  in  the  sputum  of  pertussoid  patients  a  bacterium 
belonging  to  the  genus  Ustiligo,  Tul. ;  with  this  he 


416  BACTERIA  IN  INFECTIOUS  DISEASES. 

inoculated  the  tracheal  mucous  membrane  of  tracheo- 
tomized  rabbits  and  noted  the  results.  He  invariably 
produced  a  spasmodic  catarrhal  affection  resembling 
whooping-cough,  and  he  observed  that  the  bacteria 
do  not  penetrate  the  epithelium,  but  live  on  the  sur- 
face of  the  mucous  membrane,  to  the  detriment  of  the 
latter. 

"  Tschamer,  of  Gratz,  working  in  the  same  depart- 
ment of  micro-pathology,  has  lately  found,  in  the  expec- 
toration of  pertussis,  a  microphyte,  which  he  identifies 
with  a  black  mould  which  develops  on  orange-peel. 
This  he  thinks  that  he  has  proved  by  different  cultures. 
Satisfied  of  the  identity,  he  took  some  of  the  black 
powder  which  constitutes  the  mould  of  orange-peel  and 
experimented  with  it  on  himself,  inhaling  the  powder  as 
deeply  as  he  could.  At  first  no  effect  was  observed, 
but  after  eight  days  he  began  to  have  convulsive  fits  of 
coughing,  and  expectorated  the  fungus  in  abundance. 

'*  He  explains  the  phenomena  of  whooping-cough  in 
this  way.  After  an  incubation  of  seven  days,  these  mi- 
crophytes determine  an  irritation  of  the  bronchi  which 
induces  catarrh  and  spasmodic  cough ;  then,  as  the  irri- 
tation increases,  the  expectoration  becomes  more  abun- 
dant and  eliminates  the  fungoid  organisms. 

"  Dolan,  in  repeated  experiments,  found  that  by  in- 
oculating rabbits  with  the  sputum  of  whooping-cough 
patients,  he  not  only  induced  a  catarrhal  spasmodic 
affection,  but  the  death  of  the  animal  generally  ensued. 
Inoculation  with  the  blood  of  such  patients  was  without 
effect.  This  certainly  seems  to  confirm  the  conclusions 
of  Letzerich,  that  the  materies  morbi,  —  be  it  a  bacillus, 
or  be  it  what  it  may,  —  lives  on  the  surface  of  the  epi- 
thelium, and  does  not  get  into  the  blood." l 

1  The  Medical  Record,  February  17, 1883,  p.  185. 


YELLOW  FEVER.  417 

The  writer  has  italicized  the  sentence  in  which 
the  editor  of  the  "Medical  Record"  has  inciden- 
tally remarked  that  the  death  of  the  animal  gen- 
erally ensues,  and  would  respectfully  call  attention 
to  his  experiments  relating  to  a  fatal  form  of  septi- 
caemia in  rabbits  resulting  from  the  subcutaneous 
injection  of  the  saliva  of  healthy  individuals. 

YELLOW  FEVER.  —  In  a  paper  contributed  to 
the  American  Journal  of  the  Medical  Sciences 
(April,  1873),  the  writer  has  stated  the  a  priori 
argument  in  favor  of  the  germ  theory  as  regards 
the  etiology  of  yellow  fever  in  the  following 
language : 

"  There  are  three  agents,  to  one  of  which  we  must  (in 
the  present  state  of  our  knowledge)  refer  the  poison, 
which,  by  its  action  upon  the  human  system,  produces 
yellow  fever,  viz. : 

"  (a)  A  volatile  inorganic  matter. 

"  (&)  A  lifeless  organic  matter  of  the  nature  of  a  fer- 
ment, which,  by  catalytic  action,  is  capable  of  trans- 
forming otherwise  (comparatively)  harmless  substances, 
present  in  the  earth  or  in  the  atmosphere,  into  the  ma- 
teiies  morbi  of  yellow  fever. 

"  (c)  A  living  germ,  capable,  under  favorable  con- 
ditions as  to  heat,  moisture,  etc.,  of  rapid  self-multi- 
plication, and  acting,  either  directly,  or  indirectly  by 
catalytically  transforming  other  substances  into  the 
efficient  cause  of  the  disease. 

"  That  the  poison  is  of  the  latter  nature,  is,  I  con- 
ceive, the  only  theory  consistent  with  the  observed  facts 
in  regard  to  the  origin  and  propagation  of  the  disease, 
:md  upon  it  all  the  otherwise  contradictory  facts  are 


418  BACTERIA  IX   INFECTIOUS   DISEASES. 

reconcilable.  In  support  of  this  I  will  first  submit  a 
few  concise  propositions  which  seem  to  me  capable  of 
proof,  and  will  then  briefly  discuss  these  propositions, 
and  the  legitimate  inferences  to  be  drawn  from  them : 

"  1.  The  yellow  fever  poison  is  not  an  emanation  from 
the  persons  of  those  sick  with  the  disease. 

"  2.  It  is  not  generated  by  atmospheric  or  telluric  influ- 
ences. A  certain  elevation  of  temperature  is,  however, 
necessary  for  its  multiplication  ;  and  its  rapid  increase  is 
promoted  by  a  moist  atmosphere,  and  probably  by  the 
presence  of  decomposing  organic  matter. 

"  3.  The  poison  is  portable  in  ships,  goods,  clothing,  etc., 
and  a  minute  quantity  is  capable  of  giving  rise  to  an  exten- 
sive epidemic. 

"  4.  Exposure  to  a  temperature  of  32°  Fahrenheit  com- 
pletely destroys  it. 

"  5.  It  may  remain  for  an  unknown  length  of  time  in  a 
quiescent  state,  when  not  subjected  to  a  freezing  temper- 
ature, or  exposed  to  the  conditions  necessary  to  its  mul- 
tiplication, and  may  again  become  active  and  increase 
indefinitely  when  those  conditions  prevail. 

"  If  the  first  three  propositions  be  proven,  viz.,  that 
the  poison  is  portable,  that  a  small  quantity  may  in- 
crease indefinitely,  independently  of  the  human  body, 
and  that  it  is  not  produced  by  atmospheric  influences, 
then  the  necessary  inference  is,  that  it  is  capable  of  self- 
multiplication,  which  is  a  property  of  living  matter 
only." 

The  propositions  above  stated  were  supported,  in 
the  paper  referred  to,  by  facts  observed  during 
a  local  epidemic,  which  occurred  on  Governor's 
Island,  New  York  harbor,  during  the  summer  of 
1870.  Other  local  epidemics,  since  observed  by 
the  writer,  and  the  recorded  facts  relating  to  nu- 


YELLOW  FEVER.  419 

merous  outbreaks  of  limited  extent,  and  to  the 
extended  epidemic  in  the  United  States  in  1878, 
followed  by  a  reappearance  of  the  disease  in  Mem- 
phis in  1879,  strongly  support  these  propositions, 
and  the  inference  drawn  from  them  as  to  the  na- 
ture of  the  yellow  fever  poison.  It  will  be  seen, 
however,  that  our  propositions,  if  accepted  as 
proven,  do  not  necessarily  lead  us  to  the  conclu- 
sion that  the  yellow  fever  germ  multiplies  within 
the  bodies  of  those  sick  with  the  disease.  On  the 
other  hand,  if  the  first  proposition  is  true,  it  seems 
altogether  probable  that  it  does  not  multiply  with- 
in the  bodies  of  the  sick,  but  that  the  poison  is 
evolved  as  a  result  of  its  vital  activity  during  the 
decomposition  of  the  dead  organic  material  which 
serves  as  pabulum  for  its  growth.  The  observed 
facts  relating  to  the  epidemic  prevalence  of  the 
disease  indicate  that  decomposing  animal  matter 
furnishes  a  suitable  nidus  for  the  germ,  and  conse- 
quently the  dead  body  of  a  yellow  fever  patient 
should  constitute  such  a  nidus,  even  if  the  living 
body  does  not.  As  a  matter  of  fact,  infection 
has  very  frequently  been  traced  to  dead  bodies, 
whereas  there  is  abundant  evidence  to  show  that 
persons  contract  yellow  fever  by  exposure  in  in- 
fected localities,  and  not  by  contact  with  those  sick 
with  the  disease.  Bedding  charged  with  organic 
emanations  from  the  body  of  a  sick  person  is  also 
a  suitable  nidus  for  the  germ.  But  the  infectious 
character  of  infected  bedding  seems  to  be  acquired 
in  infected  localities  rather  than  to  be  due  to  infec- 


420  BACTERIA  IN  INFECTIOUS   DISEASES. 

tion  by  sick,  persons.  A  statement  of  the  evidence 
which  has  led  the  writer  to  this  conclusion  would 
be  out  of  place  in  the  present  volume,  and  with- 
out further  remark  we  must  proceed  to  consider 
the  experimental  evidence  in  favor  of  our  a  priori 
reasoning.  It  must  be  admitted  that  this  is  very 
.unsatisfactory. 

The  writer's  personal  investigations  are  recorded 
in  the  "Preliminary  Report  of  the  Havana  Yellow 
Fever  Commission  of  the  National  Board  of  Health," 
extracts  from  which  report  are  given  below.  Un- 
fortunately, the  time  allotted  to  this  investigation 
—  three  months  —  was  entirely  too  short  to  make 
a  thorough  experimental  study ;  and  much  of  this 
valuable  time  was  necessarily  consumed  in  perfect- 
ing methods  of  research,  and  in  gaining  a  knowl- 
edge of  micro-organisms  encountered  on  every  side 
which  rvere  not  yelloio  fever  germs,  but  which  could  not 
be  excluded  from  consideration  until  this  fact  was 
demonstrated. 

Evidently  an  extended  acquaintance  with  the 
bacterial  organisms  found  during  life  and  after 
death  in  the  bodies  of  persons  not  suffering  from 
yellow  fever,  and  familiarity  with  the  most  ap- 
proved methods  of  isolating  and  cultivating  these 
organisms,  would  have  been  of  great  advantage  to 
the  investigator.  But  this  preliminary  knowledge 
aii'l  special  training  was  of  the  most  imperfect 
character.  It  was  therefore  evident  that  unusual 
scientific  caution  would  be  required  to  compen- 
sate, as  far  as  possible,  for  a  lack  of  previous  special 


YELLOW  FEVER.  421 

preparation  for  the  work  in  hand  ;  and  to  avoid 
the  announcement  of  pseudo-discoveries  which, 
when  heralded  by  an  enthusiastic  but  ignorant 
explorer,  are  sure  to  pass  current  for  a  time,  inas- 
much as  a  majority  of  the  profession  find  no  time 
for  personal  investigations,  and  do  not  realize  the 
ease  with  which  an  explorer  in  this  field  of  inves- 
tigation may  fall  into  a  serious  error. 

Extracts  from  Report  of  Havana  Commission. 

"  In  Havana,  Dr.  Sternberg  gave  a  large  share  of  his 
time  to  the  microscopic  examination  and  photography 
of  the  blood.  No  chemical  examination  was  attempted. 
The  patients  from  whom  specimens  of  blood  were  ob- 
tained were  mostly  soldiers  in  the  military  hospital  of 
San  Ambrosio.  Ninety-eight  specimens  from  forty-one 
undoubted  cases  of  yellow  fever  were  carefully  studied, 
and  one  hundred  and  five  photographic  negatives  were 
made,  which  show  satisfactorily  everything  demonstra- 
ble by  the  microscope.  These  photographs  were  mostly 
made  with  a  magnifying  power  of  1,450  diameters,  ob- 
tained by  the  use  of  Zeiss's  one-eighteenth-inch  objec- 
tive and  Tolles's  amplifier.  Probably  no  better  lens 
than  the  Zeiss  one-eighteenth  (oil  immersion)  could 
have  been  obtained  for  this  work,  and  it  is  doubtful 
whether  any  objective  has  ever  been  made  capable  of 
showing  more  than  is  revealed  by  this  magnificent  lens. 
With  the  power  used,  organisms  much  smaller  than 
those  described  as  existing  in  the  blood  of  charbon  or 
of  relapsing  fever  would  be  clearly  defined. 

"  If  there  is  any  organism  in  the  blood  of  yellow  fever 
demonstrable  by  the  highest  powers  of  the  microscope 
as  at  present  perfected,  the  photo-micrographs  taken  in 


422  BACTERIA  IN  INFECTIOUS  DISEASES. 

Havana  should  show  it.  No  such  organism  is  shown  in 
any  preparation  photographed  immediately  after  collection. 
But  in  certain  specimens,  kept  under  observation  in  cul- 
ture-cells, hyphomycetous  fungi  and  spherical  bacteria 
made  their  appearance  after  an  interval  of  from  one  to 
seven  days.  The  appearance  of  these  organisms  was, 
however,  exceptional,  and  in  several  specimens,  taken 
from  the  same  individual  at  the  same  time,  it  occurred 
that  in  one  or  two  a  certain  fungus  made  its  appearance 
and  in  others  it  did  not.  This  fact  shows  that  the 
method  employed  cannot  be  depended  upon  for  the 
exclusion  of  atmospheric  germs,  but  does  not  affect 
the  value  of  the  result  in  the  considerable  number 
of  instances  in  which  no  development  of  organisms 
occurred  in  culture-cells  in  which  blood,  in  a  moist 
state,  was  kept  under  daily  observation  for  a  week  or 
more. 

"  The  method  employed  seemed  the  only  one  prac- 
ticable for  obtaining  blood  from  a  large  number  of  in- 
dividuals without  inflicting  unwarrantable  pain  and 
disturbance  upon  the  sick.  It  was  as  follows:  One 
of  the  patient's  fingers  was  carefully  washed  with  a 
wet  towel  (wet  sometimes  with  alcohol  and  at  others 
with  water)  and  a  puncture  was  made  just  back  of  the 
matrix  of  the  nail  with  a  small  triangular-pointed  trocar. 
As  quickly  as  possible  a  number  of  thin  glass  covers 
were  applied  to  the  drop  of  blood  which  flowed,  and 
these  were  then  inverted  over  shallow  cells  in  clean 
glass  slips,  being  attached  usually  by  a  circle  of  white 
zinc  cement.  In  dry  preparations,  which  are  most  suit- 
able for  photography,  the  small  drop  of  blood  was  spread 
upon  the  thin  glass  cover  by  means  of  the  end  of  a 
glass  slip. 

"The  thin  glass  covers  were  taken  from  a  bottle 
of  alcohol  and  cleaned  immediately  before  using,  and 


YELLOW  FEVER.  423 

usually  the  glass  slips  were  heated  shortly  before  apply- 
ing the  covers,  for  the  purpose  of  destroying  any  atmos- 
pheric germs  which  might  have  lodged  upon  them. 
These  precautions  were  not,  however,  sufficient  to  pre- 
vent the  inoculation  of  certain  specimens  by  germs 
floating  in  the  atmosphere  (Penicillium  spores  and  micro- 
cocci)  ;  and  in  nearly  every  specimen  the  presence  of 
epithelial  cells,  and  occasionally  of  a  fibre  of  cotton  or 
linen,  gave  evidence  that  under  the  circumstances  such 
contamination  was  unavoidable.  It  is  therefore  believed 
that  any  organism  developing  in  the  blood  of  yellow 
fever,  or  of  other  diseases,  collected  by  the  method  de- 
scribed, or  by  any  similar  method,  can  have  no  great 
significance  unless  it  is  found  to  develop  as  a  rule  (not 
occasionally)  in  the  blood  of  patients  suffering  from  the 
disease  in  question,  and  is  proved  by  comparative  tests 
not  to  develop  in  the  blood  of  healthy  individuals,  ob- 
tained at  the  same  time  and  by  the  same  method. 

"  Tried  by  this  test  it  must  be  admitted  that  certain 
fungi  and  groups  of  micrococci,  shown  in  photographs 
taken  from  specimens  of  yellow  fever  blood  collected 
at  the  military  hospital  and  preserved  in  culture- 
cells,  cannot  reasonably  be  supposed  to  be  peculiar  to 
or  to  have  any  causal  relation  to  this  disease.  While 
we  can  claim  no  discoveries  from  the  microscopic  exam- 
ination of  the  blood,  bearing  upon  the  etiology  of  yellow 
fever,  some  interesting  observations  have  been  made 
relating  to  the  pathology  of  the  blood  in  this  disease. 

"It  is  not  intended  in  this  report  to  do  anything  more 
than  make  a  brief  reference  to  these  observations,  as  a 
comparative  study  of  the  blood  of  other  diseases  will  be 
required  to  give  value  to  them,  and  a  detailed  report 
upon  this  subject  is  to  be  made  at  some  future  time. 
The  most  important  observation  made  relates  to  certain 
granules  in  the  white  corpuscles  shown  in  many  of  the 


PLATE   X. 

FIG.  1. — Blood  from  finger  of  yellow  fever  patient  in  Military 
Hospital,  Havana,  1879  ;  fifth  day  of  sickness  ;  fatal  case.  X  400 
diameters  by  Beck's  £  inch  objective. 

FIG.  2.  —  Blood  from  finger  of  yellow  fever  patient  in  Military 
Hospital,  Havana,  1879  ;  fifth  day  ;  fatal  case.  X  1450  ;  Zeiss's 
^  inch  horn,  oil  im.  objective. 

FIG.  3.  —  White  blood  corpuscle  from  yellow  fever  blood  of  fifth 
day,  showing  fat  granules.  X  1450. 

FIG.  4.  —  White  blood  corpuscle  from  yellow  fever  blood  of  fifth 
day,  showing  fat  granules.  X  1450. 


PLATE  x. 


r  IG.  2 


YELLOW  FEVER.  425 

photomicrographs  taken.  From  the  manner  in  which 
these  granules  refract  light,  and  for  other  reasons,  they 
are  believed  by  Dr.  Sternberg  to  be  fat,  and  to  represent 
a  fatty  degeneration  of  the  leucocytes. 

"  The  blood  of  twelve  healthy  individuals  was  exam- 
ined in  Havana  for  comparison,  and  in  nearly  every  case 
an  occasional  leucocyte  was  found  to  contain  a  few  (one 
or  two)  granules  undistinguishable  from  those  found  in 
the  blood  of  yellow  fever ;  but  this  was  the  rare  excep- 
tion ;  while  in  severe  cases  of  yellow  fever  the  granules 
were  abundant,  and  nearly  every  white  corpuscle  con- 
tained some  of  them." 

The  granules  referred  to  are  well  seen  in  the 
heliotype  reproductions  of  the  writer's  photo- 
micrographs made  in  Havana.  (See  Figs.  1,  2, 
3,  and  4,  Plate  X.) 

Upon  comparing  the  granules  referred  to,  as 
seen  in  Fig.  3,  Plate  XX,  with  a  photo-micrograph 
of  the  spores  of  bacilli  (Fig.  3,  Plate  III.)  made 
with  the  same  amplification,  a  very  striking  resem- 
blance will  be  noticed.  Indeed  it  would  be  impos- 
sible to  determine  from  the  optical  appearances 
alone  that  in  one  case  we  are  dealing  with  fat- 
granules,  and  in  the  other  with  reproductive  spores. 
The  size  and  the  refractive  index  are  the  same,  or 
very  nearly  so.  These  granules  were  new  to  the 
writer  when  he  first  encountered  them  in  the 
blood  of  yellow  fever  patients,  and  it  seemed  not 
improbable  that  a  discovery  of  value  had  been 
made.  Much  time  was  accordingly  given  to  their 
study.  The  result  of  this  was  to  convince  the  writer 
that  they  were  fat-granules,  probably  developed  in 


426 


BACTERIA  IN  INFECTIOUS   DISEASES. 


the  leucocytes,  and  representing  a  fatty  degenera- 
tion of  their  protoplasm,  but  possibly  picked  up 
from  the  blood.  In  the  white  corpuscle  in  the 
centre  of  Fig.  2  it  will  be  noticed  that  these  gran- 
ules are  of  various  sizes,  and  that  they  do  not  so 
closely  resemble  bacillus  spores.  The  conviction 
that  they  were  really  fatrgranules  was  not  reached, 
however,  until  after  a  protracted  study  of  yellow 
fever  blood,  enclosed  in  germ-proof  culture-cells, 
which  admitted  of  frequent  microscopical  exami- 
nation of  their  contents.  In  these  cells  no  evidence 

was  obtained  that  these 
granules  increase  by  fis- 
sion or  grow  into  rods, 
as  we  should  expect  if 
they  were  reproductive 
bodies.  On  the  other 
hand,  they  increased  in 
size,  became  diffluent, 
and  after  a  time  the  leu- 
cocyte presented  the  ap- 
pearance of  having  been 
resolved  into  a  little 
collection  of  oil  glo- 
bules. 

The  inference  that  the  species  of  Penicillium  (see 
Fig.  27)  which  not  infrequently  appeared  in  my 
culture-cells  was  developed  from  air-borne  spores 
which  accidentally  fell  upon  the  drop  of  blood 
during  the  brief  period  required  for  hermetically 
enclosing  it,  and  not  from  spores  present  in  the 


Fig  27. 

Penicillinm  from  culture-cell  containing 
blood  of  yellow  fever  patient.  X  200. 
(Prom  photo -micrograph,  Havana, 
1879.) 


YELLOW  FEVER.  427 

blood  prior  to  its  withdrawal  from  the  body,  was 
probably  correct.  But  it  must  be  admitted  that 
the  argument  offered  in  favor  of  this  view  has  no 
great  weight,  and  that  the  inference  may  be  a 
mistake.  The  fact  that  the  fungus  only  appeared 
occasionally  in  my  culture-cells  would  be  quite 
easily  reconciled  with  its  somewhat  abundant  pres- 
ence in  the  blood  ;  for  an  organism  of  this  size 
might  be  present  in  considerable  numbers  without 
being  found  in  every  drop  drawn  from  the  ringer. 
But  direct  examination  of  very  many  specimens  of 
blood  did  not  show  it,  whereas  it  is  well  known 
that  the  spores  of  Penicittium  are  among  the  most 
numerous  of  the  organized  particles  suspended  in 
the  atmosphere ;  and  their  abundant  presence  in 
the  air  of  the  Military  Hospital  of  Havana  was 
demonstrated  by  aspiration  experiments  and  mi- 
croscopic examination. 

That  portion  of  the  Report  of  the  Havana  Com- 
mission which  relates  to  experiments  on  animals  is 
here  quoted  in  full,  as  one  of  the  objects  which  the 
writer  has  had  in  view  in  the  preparation  of  the 
present  volume  has  been  to  enable  those  who  pro- 
pose to  enter  upon  experimental  investigations 
of  this  nature  to  readily  avail  themselves  of  the 
experience  gained  by  others  who  have  preceded 
them : 

Experiments  upon  Animals. 

"  It  has  been  commonly  reported,  and  is  asserted  by 
several  writers  of  acknowledged  ability,  that  during  the 
prevalence  of  yellow  fever  certain  of  the  inferior  ani- 


428  BACTERIA  IN   INFECTIOUS   DISEASES. 

mals  exhibit  symptoms  of  sickness  which  are  attributa- 
ble to  the  influence  of  the  yellow  fever  poison. 

"  (Vide  Barton,  Cause  and  Prevention  of  Yellow 
Fever,  third  edition,  pp.  52-55 ;  Feraud,  de  la  fievre 
jaune  &  la  Martinique,  p.  271 ;  La  Roche  on  Yellow 
Fever,  Vol.  II.,  pp.  316-318  ;  Blair,  Yellow  Fever  Epi- 
demic of  British  Guiana,  third  edition,  p.  63.) 

"In  view  of  these  reports,  the  Commission  was  in- 
structed as  follows :  '  It  is  obvious  that  if  it  be  found 
possible  to  produce  some  specific  symptoms  in  some  one 
of  the  lower  animals  by  exposing  such  animals  in  local- 
ities known  to  be  capable  of  producing  the  disease  in 
man,  and  thus  to  establish  a  physiological  test  of  the 
presence  of  the  cause  of  the  disease,  we  may  even  hope 
to  be  able  to  determine  the  nature  of  and  the  natural 
history  of  this  cause,  although  prolonged  investigation 
may  be  necessary  to  effect  it.' 

"The  Commission  has  endeavored  to  carry  out  the 
views  of  the  Board  of  Health  in  this  direction,  but  in 
consequence  of  the  limited  time  at  its  disposal,  the  want 
of  a  suitable  place  to  keep  the  larger  animals,  and  the 
amount  of  work  in  other  directions  expected  from  it,  it 
has  been  found  impossible  to  make  an  exhaustive  exper- 
imental investigation.  Enough  has  been  done,  however, 
to  make  it  appear  highly  probable  that  the  sickness  and 
mortality  reported  among  animals  during  the  prevalence 
of  yellow  fever  epidemics  has  been  improperly  ascribed 
to  the  influence  of  the  yellow  fever  poison.  It  is  well 
known  that  many  of  the  inferior  animals  suffer  from 
epidemic  diseases  peculiar  to  their  several  species,  and 
this  is  especially  the  case  in  southern  latitudes.  We 
know  of  no  reason  why  such  epidemics  should  not  occur 
coincidently  with  yellow  fever  in  man,  and  it  is  not  sur- 
prising that  many  people  nnaccustamed  to  close  observa- 
tion should  attribute  the  sickness  in  man  and  in  the 


YELLOW   FEVER.  429 

animals  affected  to  the  same  cause.  In  advance  of  any 
experiments  designed  to  test  the  truth  of  such  a  deduc- 
tion, it  seemed  quite  improbable,  from  the  fact  that  the 
supposed  effect  only  results  exceptionally,  if  at  all,  while 
domestic  animals  are  frequently  exposed  in  large  num- 
bers, in  localities  visited  by  severe  epidemics  of  yellow 
fever,  without  exhibiting  any  symptoms  of  sickness. 
This  fact  is  vouched  for  by  many  competent  observers, 
and  is  verified  by  the  personal  experience  of  two  mem- 
bers of  this  Commission. 

14  Nevertheless,  in  view  of  the  reports  referred  to,  of 
the  great  importance  in  the  prosecution  of  the  investi- 
gation of  a  test  of  the  presence  of  the  poison,  and  of 
the  possibility  that  by  close  observation  and  the  use  of 
the  clinical  thermometer  some  symptoms  heretofore 
overlooked  might  be  discovered  sufficient  to  serve  as 
such  a  test,  it  was  evidently  imperative  that  experiments 
should  be  tried  in  this  direction.  Arrangements  were 
accordingly  made  before  leaving  New  York  for  a  supply 
of  animals  as  required,  and  on  the  24th  of  July  the 
following  were  received,  per  steamer  '  Niagara,'  viz. : 
Four  dogs,  two  cats,  six  rabbits,  six  guinea-pigs,  one 
monkey,  six  chickens,  twelve  pigeons,  and  two  geese. 
Subsequently  (August  30)  six  more  dogs  were  received. 

"  All  of  these  animals  were  carefully  observed,  and 
various  experiments  were  tried  for  the  purpose  of  test- 
ing their  susceptibility  to  the  influence  of  the  yellow 
fever  poison.  The  details  of  these  experiments  are 
given  in  a  special  report  to  the  National  Board  of  Health, 
dated  October  15.  It  is  not  deemed  necessary  to  give 
these  details  in  the  present  report,  but  the  general  state- 
ment may  be  made  that  the  results  were  negative.  No 
symptoms  were  produced  in  any  of  the  animals  experi- 
mented upon  which  can  fairly  be  attributed  to  the 
influence  of  the  yellow  fever  poison. 


430  BACTERIA  IN7  INFECTIOUS  DISEASES. 

"  The  clinical  thermometer  was  constantly  used  for 
the  purpose  of  recognizing  any  slight  febrile  movement 
which  might  possibly  occur,  and  the  blood  was  examined 
microscopically  from  time  to  time.  As  the  experiments 
made  gave  no  promise  of  positive  results,  the  Com- 
mission did  not  feel  justified  in  giving  more  time  to  this 
portion  of  the  investigation.  It  is,  however,  of  the 
opinion  that  the  reports  heretofore  referred  to,  and  the 
importance  of  a  physiological  test  of  the  presence  of 
the  poison  would  justify  the  National  Board  of  Health 
in  pursuing  this  inquiry  in  future,  especially  with  such 
animals  as  this  Commission  has  not  experimented  upon. 
A  few  experiments  are  here  given  as  examples  of  those 
made : 

"  Exp.  No.  1.  —  On  the  morning  of  July  28,  four 
days  after  arrival  in  Havana,  the  following  animals  were 
exposed  on  board  the  infected  brig  4  John  Welch,  Jr.,' 
viz. :  two  dogs,  two  cats,  one  monkey,  two  rabbits,  three 
guinea-pigs,  two  geese,  three  chickens.  The  time  of 
exposure  was  forty-eight  hours,  at  the  expiration  of 
which  time  the  animals  (in  cages)  were  brought  back 
to  the  laboratory.  The  'Welch '  was  a  very  foul  ship, 
and  was  loaded  with  molasses.  During  the  time  the 
animals  remained  on  board  six  of  her  crew  (all)  were 
down  with  yellow  fever.  After  bringing  the  animals 
back  to  the  laboratory,  the  temperature  of  each  was 
carefully  taken,  and  daily  observations  were  continued 
for  some  time  after.  No  symptoms  of  sickness  presented 
themselves,  except  in  the  case  of  one  dog.  This  animal 
suffered  a  sharp  attack  of  fever,  but  it  is  believed  that 
the  case  was  one  of  a  disease  common  to  imported  dogs 
in  Cuba,  known  as  romadizo,  a  disease  the  clinifal  history 
of  which  is  very  different  from  that  of  yellow  fever.1 

1  See  special  report  to  National  Board  of  Health,  dated  October  15,  for 
full  history  of  this  case. 


YELLOW  FEVER.  431 

"  Exp.  No.  4.  —  Injected  yellow  fever  blood,  one  and 
a  half  drachms,  of  first  day,  into  femoral  vein  of  dog 
No.  3.  Blood  obtained  by  cupping  from  patient  in  civil 
hospital  and  mixed  with  a  small  quantity  of  soda  bicarb., 
to  prevent  coagulation.  Result,  entirely  negative. 

"  Exp.  No.  10.  —  One-half  of  a  blanket  from  a  yellow 
fever  patient's  bed  was  placed  in  the  cage  with  dog 
No.  4,  and  left  there  for  several  days.  No  result. 

"•  Exp.  No.  11.  —  Dog  No.  5  was  allowed  no  water 
for  two  days,  except  a  supply  in  which  the  other  half 
of  this  blanket  (Exp.  No.  10)  had  been  washed.  No 
result." 

Other  experiments  were  made,  in  which  the 
blood  of  yellow  fever  patients,  obtained  post  mortem, 
was  injected  into  rabbits  and  guinea-pigs  with 
fatal  results.  But  no  importance  was  attached  to 
these  experiments,  as  several  hours  had  in  every 
case  elapsed  after  the  death  of  the  patient  before  a 
post  mortem  examination  was  obtained  and  the  blood 
collected.  It  is  well  known  that  putrid  blood  kills 
rabbits,  and  also  that  the  blood  of  scarlet  fever 
and  other  diseases,  obtained  post  mortem,  produces 
death  when  injected  beneath  the  skin  of  these 
animals.  Similar  results  follow  the  injection  of 
other  material  containing  the  bacteria  of  putre- 
faction, as  shown  by  the  following  experiment 
made  in  New  Orleans  at  a  time  when  yellow  fever 
was  not  prevalent  : 

Exp.  No.  13.  —  October  7,  9  A.  M. —  Injected 
into  right  flank  of  rabbit  1.35  c.  c.  of  water  shaken 
up  with  a  little  material  scraped  from  the  surface 
of  gutter-mud  in  front  of  my  laboratory.  The 


432  BACTERIA  IN  INFECTIOUS   DISEASES. 

animal  was  found  dead  at  8.30  A.  M.  October  9, 
and  had  evidently  been  dead  some  hours.  Post 
mortem  examination  shows  diffuse  cellulitis  and 
gangrenous  sloughing  of  the  integument  and  sub- 
jacent tissues  of  the  right  side  of  the  belly.  So 
extensive  has  been  this  sloughing  that  the  intes- 
tines are  exposed.  A  very  offensive  odor  of  putre- 
faction is  given  off  by  the  gangrenous  tissues. 

Having  reported  my  own  failure  to  find  the 
yellow  fever  germ,  I  must  now  refer  to  the  recent 
announcements  of  its  discovery  in  Mexico  by  Dr. 
Carmona,  and  in  Brazil  by  Dr.  Freire.  According 
to  the  first-named  observer,  the  parasitic  element 
is  found  in  the  blood,  in  black  vomit,  and  in  the 
urine  of  yellow-fever  patients. 

The  following  description  is  copied  from  the 
"Medical  News"  of  July  21,  1883  : 

44  The  general  agent  wanting  in  none  of  these  sub- 
stances is  a  granular  matter,  only  seen  with  a  micro- 
scope of  1,500  diameters,  very  abundant,  ovoid,  and 
slightly  }rellow,  which  appeared  to  have  filaments  similar 
to  vibrating  ciliae,  and  having  peculiar  movements,  with 
a  tendency  to  repeat  these  again  and  again.  At  rare 
intervals  it  curls  itself  in  its  greater  diameter,  and  gener- 
ally arranges  itself  on  its  side,  gradually  approximating 
the  extremities  until  they  meet ;  then  it  regains  its 
ovoid  form,  which  is  similar  to  that  of  the  prostate 
gland.  These  granulations  are  capable  of  increasing  or 
maturing,  and,  under  special  conditions,  gradually  lose 
their  first  movement,  and  then  unroll  themselves  into 
spherical  bodies  of  yellow  color,  uniform  aspect  and 
dimensions,  eight  or  ten  times  larger  than  the  first 


YELLOW  FEVER.  433 

granulations.  These  are  from  5  to  12  /x  in  diameter. 
These  large  granulations  were  those  which  first  attracted 
attention  in  the  urine  of  the  patients  first  examined,  and 
since  found  in  the  cellular  tissues,  serum  of  blisters, 
and  other  points  of  the  organism.  There  were  in  the 
urine  threads,  evidently  mycelia,  —  some  so  large  as  to 
cover  the  whole  field  of  view,  others  smaller ;  and, 
besides,  there  were  abundant  fragments,  of  various  forms 
and  dimensions.  Some  were  more  delicate  and  of  a 
cellular  aspect ;  others  more  compact  and  larger,  of  a 
brilliant  yellow  color  and  of  fatty  aspect ;  some  of 
a  more  reddish  color ;  others  emerald  green  ;  still  others, 
but  much  more  rare,  of  a  blue  color.  Their  diameters 
varied  from  2  to  20  /*.  Cells  were  frequently  encountered 
completely  empty,  of  rounded  or  pyriform  shape  and 
variable  dimensions.  Many  of  these  cells  were  not  entirely 
empty,  but  contained  a  red  or  yellow  granular  material, 
similar  to  the  points  observed  in  the  gold-stone." 

The  writer  has  ventured  to  italicize  this  descrip- 
tion of  these  partially  empty  cells,  as  it  recalls  to 
his  mind  a  story  told  him  by  his  friend,  Dr.  J.  J. 
Woodward,  of  the  United  States  Army,  whose  skill 
as  a  microscopist  is  pretty  generally  recognized, 
both  in  this  country  and  in  Europe. 

Dr.  Woodward  states  that  several  years  since  a 
distinguished  (?)  professor  from  one  of  the  Western 
cities  came  to  Washington  to  show  him  the  germ 
of  malarial  fever  which  he  had  recently  discovered. 
An  examination  of  his  specimens  showed  that  the 
supposed  alga  (cryptococcus)  was  nothing  more  nor 
less  than  the  little  depressions  in  the  surface  of  the 
glass  slide  upon  which  his  material  was  mounted, 

28 


434  BACTERIA  IN  INFECTIOUS  DISEASES. 

filled  with  the  grains  of  rouge  powder  used  by  the 
manufacturers  for  polishing  these  slides.  These 
little  crypts,  partly  filled  with  grains  of  red  or 
yellow  rouge  powder,  are  very  abundant  on  the 
surface  of  some  glass  slides. 

And  this  recalls  a  mistake  made  by  the  writer 
soon  after  his  arrival  in  Havana  in  1879.  Upon 
aspirating  the  air  in  front  of  my  laboratory  through 
a  small  aperture,  against  a  thin  glass  cover  smeared 
with  glycerine,  and  examining  this  with  a  high 
power  (Zeiss  T^  in.),  it  was  found  that  a  variety 
of  particles  of  considerable  size,  such  as  pollen 
grains,  spores  of  PemcOtium,  starch  grains,  etc.,  had 
been  arrested ;  and  also  that  the  specimen  con- 
tained a  large  number  of  spherical  and  rod-shaped 
bodies,  which  were  supposed  to  be  bacteria.  A 
few  days  later,  upon  examining  specimens  of  yel- 
low fever  blood  spread  upon  thin  glass  covers, 
similar  bodies  were  discovered.  Photo-micrographs 
were  made,  which  showed  these  minute  spherical 
and  rod-like  bodies  interspersed  among  the  blood- 
corpuscles  ;  and  distinguished  physicians,  who  have 
since  inspected  these  photographs,  have  supposed, 
before  hearing  an  explanation  of  their  real  nature, 
that  they  were  really  bacterial  organisms.  This 
was  my  own  opinion  when  I  first  saw  them,  but  I 
noticed  that  they  did  not  seem  to  be  in  exactly 
the  same  focal  plane  as  the  blood-corpuscles.  I 
therefore  resorted  to  the  simple  expedient  of  wash- 
ing the  blood  from  the  cover-glass  and  remounting 
this  over  a  circle  of  cement.  Upon  now  examin- 


YELLOW  FEVER.  435 

ing  it  with  the  same  power,  I  found  that  while  the 
blood-corpuscles  had  disappeared,  these  pseudo-bac- 
teria still  remained,  —  showing  that  they  were  at- 
tached to  or  imbedded  in  the  thin  glass  cover.  I 
have  since  examined  numerous  glass  covers  that 
had  been  thoroughly  cleaned  by  means  of  nitric 
acid,  first,  and  distilled  water  or  alcohol  afterwards, 
and  not  infrequently  I  have  found  these  same 
objects,  which  are  only  to  be  seen  by  the  use  of 
high  powers. 

But  this  is  perhaps  an  unwarrantable  digression, 
and  I  proceed  to  quote  from  the  author  mentioned  : 

"  These  same  elements  were  found  in  the  vomited 
matter,  having  a  white  or  greenish-yellow  color,  being 
especially  abundant  in  large  mycelial  threads.  In  some 
cases  there  were  ovoid  cells,  which  appeared  to  be 
due  to  the  alcoholic  fermentation  described  by  Pasteur. 
In  these  liquids,  the  spherical,  yellow  and  elementary 
granules  suffered  the  same  changes  as  already  noticed 
in  the  urine.  The  black  vomit  sediment  appeared  to  be 
formed  for  the  greater  part  of  blackened  mycelial  threads, 
and  other  bodies  of  different  forms  and  sizes,  also  black. 
There  were  also  present  yellow  or  greenish  threads  and 
elemental  granules." 

To  this  fungus  of  many  forms  and  many  colors 
the  discoverer  has  given  the  name  "  Peronospera 
Mea." 

The  writer  failed  to  find  anything  corresponding 
with  this  description  in  his  examinations  of  blood, 
urine,  and  black  vomit,  while  in  Havana,  but  reports 
as  follows : 


436  BACTERIA  IN  INFECTIOUS  DISEASES. 

"  Organic  fluids,  such  as  urine,  black  vomit,  arid  the 
fluid  from  the  interior  of  unripe  cocoanuts,  exposed  in 
the  laboratory,  very  soon  became  filled  with  a  variety 
of  vegetable  organisms,  bacteria,  torulse,  vibriones,  and 
other  fungi,  such  as  are  found  under  similar  circum- 
stances in  all  parts  of  the  world.  Most  of  these  were 
well-known  arid  common  forms ;  some  may  have  been 
peculiar  to  the  latitude  or  even  to  localities  infected 
with  yellow  fever,  but  to  decide  this  question  would 
require  a  more  precise  knowledge  in  regard  to  these 
low  forms  of  vegetable  life  than  was  possessed  by  any 
member  of  the  Commission,  or,  indeed,  than  is  likely  to 
be  found  even  among  those  who  have  devoted  the  most 
attention  to  this  branch  of  study,  which  is  acknowledged 
by  all  to  be  yet  in  its  infancy. 

"  Photo-micrographs  were  made  of  some  of  these  forms, 
and  it  is  suggested  that  photographic  representations  of 
all  forms  found  in  southern  parts  of  the  United  States  at  a 
time  when  yellow  fever  does  not  prevail,  should  be  made 
in  advance  of  the  next  epidemic,  so  that  any  unusual 
form  presenting  itself  then  may  receive  the  special 
attention  of  future  investigators  "  (I.  c.). 

In  the  first  edition  of  this  work  (Fig.  4,  Plate  II. 
and  Figs.  1  and  2,  Plate  III.)  photographs  from 
nature  are  given  of  some  of  the  organisms  which 
were  found  most  abundantly  in  yellow-fever  urine. 
It  may  be  that  one  of  these,  or  some  one  of  the 
many  organisms  which  Carmona  has  included  in 
his  description,  is  the  veritable  germ  of  yellow 
fever ;  but  this  is  a  mere  hypothesis,  not  supported 
by  the  slightest  evidence.  At  the  time  of  my 
visit  to  Havana  I  had  not  perfected  my  method  of 
conducting  culture  experiments  (see  p.  178),  and 


YELLOW  FEVER.  437 

if  I  had  been  fully  prepared  for  the  work,  could 
not  have  found  the  time  to  obtain  pure  cultures 
of  each  micro-organism  encountered,  and  to  make 
inoculation  experiments  for  the  purpose  of  deter- 
mining whether  any  one  of  them  had  specific 
pathogenic  properties.  Pasteur  was  engaged  for 
several  years  in  his  study  of  pebrine,  the  parasitic 
disease  of  silkworms -upon  which  he  may  be  said 
to  have  founded  his  scientific  reputation.  That  the 
etiology  of  yellow  fever  was  not  worked  out  during 
the  three  months'  stay  of  the  Havana  Commission 
in  Cuba  cannot  therefore  appear  surprising  to 
those  who  know  the  difficulties  of  such  an  under- 
taking; and  if  Dr.  Carmona,  or  Dr.  Somebody-else 
succeeds  in  carrying  off  the  laurels  due  to  a  dis- 
coverer, it  will  be  rather  a  matter  of  luck  than  of 
science,  unless  he  attacks  the  problem  by  the 
painstaking  and  timetaking  methods  which  have 
been  perfected  by  Pasteur,  Koch,  and  other  pio- 
neers in  this  line  of  investigation.  Dr.  Carmona 
says : 

"  If  a  portion  of  urine  be  allowed  to  evaporate  spon- 
taneously, and  the  residue  be  examined  microscopically, 
the  protoplasmic  substance  containing  abundant  spheri- 
cal yellow  granulations,  mycelial  tubes,  and  crystals  of 
cholesterine  and  tyrosine,  before  mentioned,  are  seen. 
The  free  extremities  of  many  of  the  mycelial  threads 
were  gradually  dilated,  somewhat  resembling  the  ex- 
tremity of  the  olfactory  bulb."  These  dilated  extrem- 
ities Carmona  calls  oogonos,  and  they  measure  from 
10  to  60  fj.. 

Yellow  fever  urine  is  an  acid  albuminous  fluid, 


438  BACTERIA  IN  INFECTIOUS  DISEASES. 

and  a  suitable  culture-medium  for  a  variety  of  bac- 
terial organisms  and  microscopic  fungi.  At  the 
extremity  of  the  urethral  canal,  bacteria  are  always 
found  in  considerable  numbers,  and  the  urine  of 
healthy  persons,  or  of  yellow  fever  patients,  is 
necessarily  contaminated  with  these  when  it  is 
voided.  Urine  "  allowed  to  evaporate  spontane- 
ously" is  presumably  exposed  to  the  air  and  to 
inoculation  with  the  numerous  germs  which  it 
contains. 

Dr.  Carmona  says  :  "  The  black  vomit  sediment 
appeared  to  be  formed  for  the  greater  part  of 
blackened  mycelial  threads,  and  other  bodies  of 
different  forms  and  sizes,  also  black." 

The  uniform  testimony  of  competent  micro- 
scopists  who  have  heretofore  examined  black 
vomit  is,  that  the  dark  color  is  due  to  the  presence 
of  blood,  altered  by  the  acid  secretions  of  the 
stomach,  which  escapes  from  the  hypersemic  mu- 
cous membrane  during  the  later  stages  of  the 
disease,  when  passive  hemorrhages  are  common. 
The  writer  has  repeatedly  verified  this  fact,  and, 
while  in  Havana,  made  photo-micrographs,  which 
show  that  the  little  dark-colored  flocculi  in  the 
vomited  material  are  made  up  of  decolorized  blood- 
corpuscles  and  of  amorphous  masses  of  dark  ma- 
terial which  is  presumably  haemoglobin  from  these 
decolorized  corpuscles,  changed  by  the  acid  secre- 
tions of  the  stomach.  A  microscopic  examination 
of  black  vomit  or  of  the  transparent  acid  fluid 
ejected  at  frequent  intervals  before  hemorrhages 


YELLOW  FEVER.  439 

occur,  shows  that  it  contains  epithelium  from  the 
mouth  and  bacteria  of  various  forms.  This  is  not 
surprising  when  we  remember  that  every  drop  of 
saliva  swallowed  is  charged  with  a  variety  of  these 
minute  plants.  To  decide  whether  any  one  of 
these  bears  a  causal  relation  to  the  disease,  would 
require  extended  culture-experiments,  and  the 
administration  of  a  pure  culture  to  man  himself,  as 
a  test  of  specific  pathogenic  power,  unless  satis- 
factory evidence  can  be  obtained  that  some  one  of 
the  lower  animals  is  susceptible  to  the  disease. 

A  more  recent  claim  to  the  discovery  of  the 
yellow  fever  germ  is  that  made  by  Dr.  Freire  of 
Brazil. 

I  quote  again  from  the  "  Medical  News  "  (July 
7,  1883,  p.  13): 

"  Dr.  Freire  recognizes  in  the  blood  of  yellow  fever 
patients  a  cryptococcus  to  which  he  has  given  the  specific 
title  of  Xanthogenicus.  In  the  phases  of  its  development 
it  appears  as  minute  points,  or  as  large  round  cells  with 
grayish  or  fringed  margins,  and  bright  transparent 
centres.  Besides  these  there  are  occasionally  seen  trans- 
parent granulations,  aggregated  in  a  yellowish  matrix. 
A  gramme  of  blood  charged  with  these  organisms,  from 
a  yellow  fever  patient,  was  injected  into  the  veins  of  a 
rabbit,  which  died  in  a  quarter  of  an  hour  with  tetanic 
convulsions.  ...  At  the  autopsy  visceral  congestions 
were  found,  similar  to  those  seen  in  persons  dead  of 
yellow  fever,  and  the  blood  was  found  to  contain  the 
cryptococcus  which  was  present  in  that  which  had  been 
inoculated. 

"  A  gramme  of  the  blood  of  this  rabbit  was  injected 


440  BACTERIA  IN  INFECTIOUS  DISEASES. 

hypodermically  into  a  guinea-pig,  which  died  at  the  end 
of  some  hours.  Its  blood  was  found  to  contain  an  ex- 
traordinary quantity  of  the  cryptococcus.  A  second 
guinea-pig  was  inoculated  by  hypodermic  injection  with 
the  blood  of  the  first  one,  and  after  some  hours  the 
animal  appeared  feverish  and  oppressed,  with  cold  ears 
and  paws,  trembling,  and  blackish  vomiting.  It  died  in 
a  short  time,  and  its  blood  showed  an  infinity  of  the 
characteristic  organisms. 

"  Dr.  Freire  considers  that  these  experiments  estab- 
lish the  parasitic  nature  of  yellow  fever,  arid  that  the 
parasite  C.  Xanthogenicus,  is  found  in  every  undoubted 
case  of  the  disease.  He  has  also  discovered  and  is- 
olated the  alkaloid  from  the  black  vomit,  which  he 
regards  as  a  product  or  excretion  of  the  microbes.  He 
considers  that  the  color  of  black  vomit  is  not  due  to 
altered  blood,  but  to  the  cryptococcus.  He  regards 
cemeteries  as  perennial  foci  of  the  disease.  Some  earth 
was  taken  from  the  grave  of  a  man  who  had  been  buried 
a  year  before.  A  guinea-pig  shut  up  in  a  confined 
space  with  this  earth  died  in  five  days.  Its  blood  was 
literally  crammed  with  the  cryptococcus  in  various  stages 
of  evolution ;  its  urine  was  albuminous,  and  its  brain 
and  intestines  yellow  with  the  peculiar  pigment  of  the 
microbe." 

The  writer  is  not  prepared  to  estimate  the  value 
of  the  evidence  here  offered,  inasmuch  as  we  are 
not  informed  whether  the  yellow  fever  blood  used 
in  the  first  inoculation  experiment  was  obtained 
post  mortem  or  ante  mortem.  It  would  be  interesting 
also  to  know  whether  the  cryptococcus  was  ob- 
tained in  blood  drawn  with  proper  precautions 
during  the  lifetime  of  the  patient.  While  in 


YELLOW  FEVER.  441 

Havana,  the  writer  paid  very  little  attention  to 
post  mortem  blood ;  but  it  was  noticed  that  in  blood 
drawn  during  the  last  hours  of  life  the  seritm  was 
tinted  yellow,  and  the  red  corpuscles  were  paler 
than  normal  from  a  loss  of  haemoglobin.  Any 
albuminous  granular  material  in  post  mortem  blood 
—  from  disintegration  of  the  corpuscles,  etc. — 
would  therefore  be  likely  to  be  stained  yellow  by 
this  pigment 

Hineman,  a  very  competent  German  physician 
practising  in  Vera  Cruz,  has  not  been  more  success- 
ful than  the  writer  in  finding  the  Peronospera  lutea  of 
Carmona,  or  the  Cryptococcm  Xanthogenicus  of  Freire, 
in  the  blood  of  yellow  fever  patients,  before  death. 
He  examined  the  blood  of  patients  in  the  last 
stage  of  the  disease,  taking  blood  from  the  hand, 
thinning  it  with  artificial  serum,  and  brine/ing  it  at 
once  under  the  microscope.  He  says :  "  In  nine 
cases  so  examined  not  the  slightest  deviation  from 
normal  blood  could  be  found.  .  .  .  No  organisms 
were  found.'* * 

i  Arch.  f.  path.  Anat.  LXXVIIL  p.  139. 


PAET   SIXTH. 


BACTERIA  IN  SURGICAL  LESIONS. 

THE  important  part  played  by  bacteria  in  sur- 
gical lesions  can  no  longer  be  questioned.  This 
is  demonstrated  (a)  positively,  by  the  ill-effects 
which  result  from  the  retention  of  discharges  con- 
taining putrefactive  bacteria  upon  the  surface  of 
open  wounds,  or  in  sinuses  and  cavities;  and  (b) 
negatively,  by  the  favorable  results  of  antiseptic 
treatment ;  and  the  fact  that  when  .the  access  of 
micro-organisms  is  prevented  by  the  integrity  of 
the  cutis,  very  severe  lesions,  attended  with  an 
abundant  exudation  of  bloody  serum,  are,  com- 
monly recovered  from  without  suppuration  or  any 
evil  result  from  the  resorption  of  this  fluid  and  of 
inflammatory  exudates.  But  this  same  material 
quickly  attains  poisonous  properties  in  the  presence 
of  bacteria,  and  not  only  exercises  a  deleterious 
local  effect,  unfavorable  to  the  repair  of  the  injury, 
but  its  absorption  now  is  attended  with  the  most 
serious  consequences. 

These  facts,  which  are  so  generally  recognized 
that  it  is  unnecessary  to  present  evidence  in  their 


BACTERIA  IN  SURGICAL  LESIONS.  443 

support,  are  in  accord  with  the  following  propo- 
sitions which  have  been  established  by  experimental 
research  and  may  be  accepted  as  fundamental 
truths  upon  which  to  base  our  reasoning  as  regards 
the  role  of  the  bacteria  in  surgical  lesions. 

(a)  The  blood  and  tissues  of  healthy  persons  do 
not,  under   ordinary  circumstances,  contain  bac- 
terial organisms. 

(b)  Putrefactive  decomposition  of  organic  fluids 
is  due  to  bacterial  organisms. 

(c)  Albuminous  fluids,  —  e.g.,  blood  and  pus, 
which    have    undergone    putrefaction,  contain    a 
potent  poison,  or  poisons,  which,  in  comparatively 
small  amount,  may  produce  death  in  the  lower 
animals. 

We  have  here  a  sufficient  foundation  for  the 
antiseptic  treatment  of  wounds.  But  in  addition 
to  this  there  are  strong  reasons  for  believing  that 
certain  species  of  bacteria  have  also  the  power 
of  invading  the  tissues,  and  producing  local  necro- 
sis, when  for  any  reason  the  vital  resistance  of 
these  tissues  is  reduced,  —  e,  g.,  from  hemorrhage, 
from  starvation,  from  crowd  poisoning,  from  septic 
poisoning.  Or  the  same  result  may  perhaps  occur 
when  the  vital  resistance  of  the  tissues  is  not  below 
par,  in  consequence  of  the  unusual  vigor  of  the 
micro-organisms,  developed  as  a  result  of  unusually 
favorable  conditions  of  environment.  As,  for  ex- 
ample, when  a  healthy  man,  recently  wounded, 
fulls  a  victim  to  hospital  gangrene  as  the  result 
of  infection  in  a  crowded  ward,  in  which  this  in- 


444 


BACTERIA  IN  SURGICAL  LESIONS. 


Fig.  28. 


factious  disease  was  in  the  first  instance  developed 
de  novo. 

The  purulent  discharge  from  wounds  not  treated 
antiseptically    always    contains    micro-organisms. 

These  are  mainly  micro- 
cocci  and  short  rods  like 
those  shown  in  Figs.  28  and 
29,  which  are  copied  from 
Cheyne's  recent  work  on 
"Antiseptic  Surgery." 

The  micrococci  repre- 
sented in  Fig.  28  were  ob- 
tained by  cultivation  in  cu- 
cumber infusion,  from  a 
wound  treated  asept'cally. 
The  orga™sms  represented 
in  Fig.  29  are  from  a  case 
of  compound  dislocation  of  the  thumb  not  treated 
aseptically.  The  rod-bacteria  in  this  figure  are 
doubtless  septic  bacteria,  properly  so  called,  which 
give  rise  to  the  putrefactive  decomposition  of  albu- 
minous fluids.  The  observations  of  Cheyne  show 
that  these  may  be  excluded  from  the  secretions  of 
wounds  by  antiseptic  treatment,  and  that,  in  this 
case,  the  pus  discharged  from  such  wounds  pre- 
sents no  evidence  of  putrefaction,  although,  in 
certain  cases,  micrococci  are  found  in  this  pus 
formed  beneath  antiseptic  dressings.  This  is  ex- 
plained by  the  greater  resisting  power  of  micro- 
cocci  to  antiseptic  agents.  Cheyne  says  : 

"  Micrococci  prefer  acid  fluids  ;  most  bacteria  prefer 
alkaline  or  neutral  fluids. 


BACTERIA  IN   SURGICAL  LESIONS. 


445 


"  Micrococci  grow,  readily,  in  fluids  containing  pro- 
portions of  carbolic  acid  in  which  bacteria  only  grow 
with  difficulty"  (Z.  <?.,  p.  244). 

The  experiments  of  the  writer  have  not  shown 
any  difference  as  regards 
the  action  of  carbolic  acid 
in  preventing  the  develop- 
ment of  these  different  or- 
ganisms in  culture-fluids ; 
but  in  the  case  of  boric  acid 
and  of  sodium  biborate  a 
very  marked  difference  was 
observed,  the  micrococcus 
of  pus  developing  freely  in  Specimen  of  discliarge  taken  from  a 
the  presence  of  0.25  per  case  of  compound  dislocation  of 

the   thumb   not  treated    asepti- 

cent  of  boric  acid,  while  B.        caljy-  x  1450.  (From  cheyne's 

.  "  Antiseptic  Surgery.") 

termo  failed   to  develop   in 

the  presence  of  one-half  this  amount.  It  is  pro- 
bable that  free  access  of  oxygen  in  the  culture- 
experiments,  and  its  exclusion,  to  some  extent  at 
least,  from  the  surface  of  wounds  treated  anti- 
septically  by  Lister's  method,  is  an  advantage  in 
favor  of  the  micrococcus  in  the  latter  case  ;  for  we 
know  that  this  may  multiply  freely  in  the  absence 
of  oxygen  in  the  pus  of  a  closed  abscess. 

While  there  is  no  question  as  to  the  injurious 
effects  of  putrefactive  bacteria  in  the  discharges 
from  wounds  when  these  are  retained  upon  an 
absorbent  surface,  or  in  a  sinus  or  pus-cavity,  the 
role  of  the  micrococcus  of  pus  has  not  been  so 
well  established.  According  to  one  view,  inflamma- 


Fig.  29. 


446  BACTERIA  IN  SURGICAL  LESIONS. 

tion  results  in  the  formation  of  pus  only  when 
this  micrococcus  is  present,  and  because  of  its 
presence.  On  the  other  hand,  it  has  been  claimed 
that  it  is  simply  present  because  it  finds  in  pus  a 
suitable  culture-medium,  and  that  its  presence  in 
this  fluid  is  without  significance.  Cheyne  is  in- 
clined to  look  upon  this  micrococcus  as  compara- 
tively harmless;  and  without  doubt  it  may  be 
present  in  the  pus  secreted  by  wounds  which  are 
healing  in  a  most  satisfactory  manner.  Cheyne 
says  : 

"It  is  certain  that  they  do  not  cause  putrefaction, 
but  they  always  cause  a  sort  of  sour,  sweaty  smell  in 
fluids, — a  smell  which  can  be  recognized  in  whatever 
fluid  they  grow :  in  other  words,  they  are  associated 
with  a  peculiar  fermentation.  Now,  the  products  of 
this  fermentation  are  but  little  irritating.  They  have 
no  acrid  taste,  nor  do  they  feel  pungent  when  applied 
to  a  cut  surface.  Hence,  probably,  it  is  that  we  find 
wounds  in  which  these  organisms  exist,  even  in  large 
numbers,  appear  often  unaffected  by  their  presence. 

"  Nevertheless,  they  can  hardly,  under  any  circum- 
stances, be  indifferent,  and  I  think  I  have  observed  that 
in  some  cases,  after  they  have  got  in,  the  wounds  do 
not  behave  quite  as  typically  as  usual ;  i.  e.,  there  may 
be  a  trace  of  suppuration,  or  a  sinus  takes  longer  to 
heal  than  one  had  any  reason  to  expect." 

To  test  the  possible  local  pathogenic  action  of 
the  micrococcus  of  pus  the  writer  made  the  follow- 
ing experiment : 

"  Exp.  No.  12.  —  August  4.  —  An  incised  wound  was 
made  with  scissors,  removing  a  fragment  of  skin  upon 


BACTERIA  IN   SURGICAL  LESIONS.  447 

each  thigh  of  a  half-grown  rabbit.  The  wound  upon 
the  right  thigh  was  moistened  with  a  culture-fluid 
(twentieth  culture)  containing  the  micrococcus  from 
gonorrhoeal  pus.  The  wounds  were  then  dressed  with 
dry  tow,  and  a  bandage  applied.  Both  healed  kindly 
without  any  undue  inflammation,  and  no  difference  was 
observed  between  the  two." 

This  single  experiment  counts  for  but  little  ;  and 
the  criticism  may  be  made  that  this  micrococcus 
was  obtained  from  gonorrhceal  pus,  and  is  perhaps 
specifically  distinct  from  the  micrococcus  of  ordi- 
nary pus,  although  it  appears  to  be  morphologically 
identical  with  it.  All  this  is  admitted,  and  the 
experiment  is  introduced  mainly  to  call  attention 
to  a  method,  which,  carefully  applied,  should 
enable  us  to  solve  the  question  as  to  the  patho- 
genic role  of  this  micrococcus.  The  writer  had 
mapped  out  for  himself  a  series  of  experiments  in 
this  direction  and  many  others  relating  to  etio- 
logical  questions,  but  circumstances  have  not  been 
favorable  for  the  prosecution  of  experimental  work, 
and  he  finds  himself,  somewhat  reluctantly,  en- 
gaged in  a  review  of  the  field,  when  it  would  be 
far  more  to  his  taste  to  interrogate  nature  by  the 
experimental  method,  and  thus  to  aid  directly  in 
the  solution  of  these  interesting  problems. 

One  of  these  problems,  with  our  present  light, 
is  very  puzzling.  It  has  been  demonstrated  by 
numerous  observers  that  this  micrococcus  of  pus  is 
uniformly  found  in  pus  obtained  from  an  acute 
abscess,  when  the  integument  covering  it  is  still 


448  BACTERIA  IN  SURGICAL  LESIONS. 

intact,  even  when  it  is  deeply  situated  in  the 
tissues  ;  and  yet  the  observations  of  Pasteur,  Koch, 
Cheyne,  and  many  others,  are  in  accord  as  to  the 
absence  of  all  micro-organisms  from  the  blood  of 
healthy  persons.  Whether,  then,  we  suppose  this 
micrococcus  to  be  the  cause  or  the  result  of  the  for- 
mation of  these  abscesses,  we  are  met  by  the  ques- 
tion, How  did  it  get  there  in  the  first  instance  ? 
In  certain  cases  such  abscesses  may  be  traced  to 
an  injury  in  which  a  slender,  sharp-pointed  in- 
strument —  e.  g.,  a  needle  or  a  thorn  —  has  pene- 
trated deeply  into  the  tissues ;  and  in  this  case  we 
may  suppose  that  micrococci  have  been  introduced 
in  this  way.  Or  possibly  the  point  of  inoculation 
may  have  been  far  removed  from  the  situation 
where  the  abscess  is  developed,  and  the  organisms 
may  have  made  their  way  in  the  blood-current  or 
through  the  lymphatics  to  this  point,  where,  for 
some  mechanical  reason,  they  have  been  arrested. 
But  this  is  speculation,  and  we  must  leave  the 
question  unsettled,  and  content  ourselves  for  the 
present  with  a  summary  statement  of  the  observed 
facts  relating  to  the  presence  of  this  micrococcus 
in  collections  of  pus  not  exposed  to  the  air. 

In  1875,  Bergeron,  in  a  communication  to  the 
French  Academy  of  Sciences,  reported,  as  the  re- 
sult of  numerous  observations  made  for  the  pur- 
pose of  ascertaining  if  the  pus  of  abscesses  contains 
bacteria,  as  follows : 

"  1.  Vibrios  are  found  in  the  pus  of  abscesses,  with- 
out any  contact  with  the  external  air,  and  without, 


BACTERIA  IN  SURGICAL  LESIONS.  449 

usually,  any  indication  that  the  organism  is  seriously 
affected  by  their  presence.  2.  We  cannot  admit  that  in 
these  cases  the  vibrios  have  penetrated  into  the  interior 
of  the  abscess  through  the  lymphatic  system,  or  through 
the  circulating  system,  both  being  intact.  The  pus  of 
warm  abscesses  in  adults  often  contains  vibrios  ;  if  they 
occur  in  the  case  of  infants  the  fact  has  not  been  ob- 
served. 3.  The  pus  of  cold  abscesses  in  the  adult,  as  in 
the  infant,  never  contains  them."  (Magnin.) 

The  vibrios  of  Bergeron  are  doubtless  identical 
with  the  micrococcus  described  by  later  observers, 
which  often  occurs  in  chains.  The  observations  of 
Billroth,  Cheyne,  and  Ogston,  are  in  accord  with 
those  of  Bergeron  as  to  the  presence  of  micrococci 
in  acute  abscesses,  and  their  absence  from  chronic 
abscesses.  Cheyne  has  shown,  however,  that  when 
these  organisms  are  proved  to  be  present  in  pus 
from  an  abscess,  by  microscopical  examination,  this 
pus  often  fails  to  fertilize  a  culture-fluid,  thus 
proving  that  the  micrococci  are  no  longer  living. 
He  says: 

"  Of  acute  abscesses,  I  had  up  to  May,  1879,  inocu- 
lated from  thirty-two  cases.  In  twenty-five  of  these  no 
growth  of  organisms  occurred,  while  from  six  micro- 
cocci  were  obtained.  In  no  case  did  I  get  bacteria  " 
(1.  c.,  p.  253). 

Ogston  examined  the  pus  from  eighty-two  ab- 
scesses, all  of  which  had  been  "hitherto  unopened." 
The  pus  was  taken  from  them  by  means  of  a  needle 
or  a  knife  while  still  flowing  from  the  incision, 
spread  out  in  a  thin  film  upon  a  slide,  immediately 

29 


450  BACTERIA  IN  SURGICAL  LESIONS. 

dried,  and  stained  with  an  aniline  dye.     Of  the 
abscesses  examined,  thirteen  were  — 

"  Chronic  typical  cold  abscesses,  whose  duration  could 
be  measured  by  months,  proceeding  from  chronic  carious 
disease  of  bone,  scrofulous  lymphatic  glands,  and  such 
like.  In  none  of  them  were  any  organisms  found. 

"  Four  were  somewhat  chronic  abscesses,  whose  dura- 
tion could  be  measured  by  weeks  ;  and  which  had  fol- 
lowed diseases  more  or  less  allied  to,  or  complicated 
with,  forms  of  blood-poisoning  and  hectic,  such  as  tonsil- 
itis,  phthisis,  scarlatina,  erysipelas,  typhoid  fever,  and 
diphtheria.  All  of  these  contained  micrococci,  and  were 
evidently  the  same  as  the  next  form. 

"  Lastly,  sixty-five  were  acute  abscesses,  whose  dura- 
tion could  be  measured  by  days,  from  all  parts  of  the 
body.  Every  one  of  these  contained  micrococci." 

The  cocci  were  found  (a)  in  chains,  usually  of  five 
or  six  elements,  but  often  much  longer — in  one 
case  three  hundred  and  twenty-one  cocci  were 
counted  in  a  single  chain ;  (b)  in  groups, "  like  the 
roe  of  a  fish" — zoogloea  masses;  (c)  in  groups  of 
three  or  four,  "  many  of  which  were  clearly,  from 
the  equal  size  and  relative  positions  of  the  cocci, 
formed  by  a  direct  division  into  fours,  or  even, 
though  more  rarely,  into  threes ;  "  (d)  in  some 
cases  unusually  large  oval  cocci  were  found,  chiefly 
in  pairs.  "  For  the  most  part  these  varieties  ex- 
isted in  separate  abscesses,  but  it  frequently 
occurred  that  an  abscess  contained  both  chains  and 
groups.  Out  of  sixty-four  abscesses  where  this 
point  was  specially  noted,  seventeen  contained 


BACTERIA  IN  SURGICAL  LESIONS.  451 

chains  only,  thirty-one  groups  only,  and  sixteen 
both  forms,  or  only  pairs." 

Ogston  was  unable  to  discover  any  difference  in 
the  character  of  the  abscesses  which  contained 
these  different  forms,  and  could  not  decide  defi- 
nitely whether  they  represented  different  species 
or  only  varieties  of  the  same  species. 

To  ascertain  whether  these  micrococci  possessed 
pathogenic  properties,  Ogston  injected  pus  con- 
taining them  into  guinea-pigs  and  mice ;  and,  for 
comparison,  pus  from  cold  abscesses,  which  con- 
tained no  micro-organisms,  into  other  animals  of 
the  same  species. 

The  invariable  result  of  twenty  experiments,  in 
which  pus  from  the  last-mentioned  source  was 
used,  was  that  no  illness  or  abscess  ensued. 

"  But  a  very  different  effect  was  produced  when 
similar  injections  were  made  with  pus  containing  micro- 
cocci.  In  every  instance,  with  the  qualifications  to  be 
presently  made,  well-marked  disease  was  set  up.  Quan- 
tities, varying  from  one  to  three  minims,  produced,  in 
the  animals  already  mentioned,  symptoms  of  blood- 
poisoning,  lasting  from  two  to  five  days.  .  .  .  These 
symptoms  became  less  marked  towards  the  end  of  the 
first  week  or  five  days.  If  the  animal  was  killed  during 
this  stage,  the  blood  in  its  right  heart  was  found  to  con- 
tain micrococci ;  single,  in  pairs,  and  in  short  chains  of 
six  or  fewer,  swimming  in  the  serum  between  the  cells. 
Around  the  site  of  injection  was  found  a  patch  of  red 
infiltration,  varying  in  size,  and  having  in  its  centre 
more  pus  than  corresponded  with  the  quantity  that  had 
been  injected.  The  pus  contained  myriads  of  micrococci 


452 


BACTERIA  IN  SURGICAL  LESIONS. 


of  the  same  nature  as  those  injected,  but  more  numer- 
ous. .  .  .  The  cocci  were  living  and  growing,  and  a 
drop  of  the  matter  injected  into  another  animal  pro- 
duced the  same  results  in  it,  and  it  on  another  animal, 
and  so  on.  No  increased  virulence  was  observable  in 
the  transference  through  a  series  of  animals.  The  red 
infiltration  around  the  abscess  showed  the  micrococci 
invading  the  neighboring  tissues,  penetrating  between 
their  cells,  and  in  colonies  or  chains,  gradually  decreas- 


Fig.  30. 
Group  of  chain  micrococci  in  pus.     x  1600     (Ogston.) 

ing  in  size,  pushing  their  way  for  a  considerable  distance 
into  the  structures  in  the  vicinity.  .  .  .  After  five  to 
seven  days  had  elapsed,  and  in  some  cases  even  earlier, 
the  animals  exhibited  a  change.  They  became  more 
active  again,  threw  off  their  lethargy,  and  seemed  well ; 
but  at  the  spot  where  the  injection  had  been  made,  there 
was  found  a  fluctuating  tumor,  gradually  increasing  in 
size,  and  presenting  all  the  signs  of  being  an  ordinary 
abscess.  When  they  were  killed  during  this  second 
stage,  micrococci  were  more  rarely  found  in  the  heart- 


BACTERIA  IN  SURGICAL  LESIONS.  453 

blood,  and  the  infiltration  of  the  organisms  into  the 
tissues  around  the  abscess  no  longer  existed,  having  been 
replaced  by  a  firm,  thick  wall  of  granulation  tissue,  in 
which  micrococci  could  seldom  be  detected,  and  which 
seemed  to  act  as  a  barrier,  preventing  or  diminishing  their 
migration  into  the  blood  and  surrounding  structures.  .  .  . 

44  On  the  presumption  that  carbolic  acid  would  de- 
stroy the  power  of  the  micrococci,  a  series  of  injections 
were  instituted  with  pus  mixed  with  equal  parts  of  a 
five  per  cent  watery  solution  of  that  substance.  These 
were  employed  on  separate  animals,  as  well  as  on  a 
different  part  of  an  animal  injected  with  unmixed  pus 
from  an  acute  abscess ;  and  in  every  case,  the  pus  so 
disinfected,  though  injected  in  larger  quantity,  produced 
no  reaction  whatever,  but  disappeared  in  the  rapid  and 
complete  way  described  under  the  experiments  with  that 
from  cold  abscesses. 

"I  next  endeavored  to  ascertain  the  temperature 
capable  of  destroying  the  power  of  micrococci.  Although, 
in  this  direction,  the  experiments  were  not  so  numerous 
as  is  desirable,  it  may  be  stated  that  pus  heated  to 
130°  Fahr.,  or  higher,  hitherto  always  failed  to  excite 
suppuration." 

This  is  strong  evidence  in  favor  of  the  view  that 
the  formation  of  acute  abscesses  is  due  to  the 
presence  of  this  micrococcus.  The  writer  has  shown 
that  its  thermal  death-point  is  140°  Fahr.,  the 
time  of  exposure  being  ten  minutes.  Ogston  does 
not  state  the  time  of  exposure  to  a  tempera- 
ture of  130°  Fahr.,  but  it  may  well  be  that  a 
somewhat  longer  exposure  than  ten  minutes  at 
this  temperature  would  also  be  fatal  to  the  mi- 
crococcus. 


454  BACTF/HIA  IN   SURGICAL  LESIONS. 

Ogston  made  also  a  large  number  of  culture- 
experiments. 

u  As  might  have  been  anticipated,  cultivations  of  pus 
of  cold  abscesses  (five  cases)  yielded  uniformly  negative 
results. 

"  Cultivations  of  pus  of  acute  abscesses  gave  at  first 
the  most  inexplicable  and  contradictory  results.  This 
was  ascribed  to  the  fact  that  the  micrococcus  in  question 
is  anagrobie,  and  cannot  grow  in  the  presence  of  oxygen. 
The  plan  was  therefore  tried  of  growing  them  in  eggs. 
Newly-laid  eggs  were  washed  in  five  per  cent  carbolic 
water ;  and,  under  spray,  a  minute  aperture  was  pierced  in 
the  larger  end.  One  minim  of  pus  from  an  acute  abscess, 
collected  under  the  strictest  antiseptic  precautions,  was 
injected  by  a  long-pointed  pure  syringe  into  the  albumen 
at  the  opposite  end  of  the  egg.  A  piece  of  protective 
was  laid  over  the  aperture.  The  egg  was  enveloped  in  a 
Lister's  dressing,  and  kept  for  ten  days  in  the  incubator 
at  98°  Fahr.  At  the  end  of  that  time  it  was  opened, 
and  my  expectations  were  fulfilled.  The  egg  was  sweet 
and  fresh  ;  its  contents  were  unaltered,  save  the  yolk 
was  somewhat  broken  up,  and  more  or  less  mixed  with 
the  albumen  ;  but  the  albumen,  and  sometimes  the  yolk 
also,  were  filled  with  enormous  chains  or  masses  (accord- 
ing to  the  sort  of  coccus  used)  of  micrococci,  growing 
quite  as  luxuriantly  as  I  had  ever  observed  them  when 
expeiimenting  on  animals.  A  drop  of  the  albumen  in- 
jected into  an  animal's  back  now  produced  typical 
abscess,  with  all  the  symptoms  already  mentioned  ;  and 
the  animal,  on  being  killed,  showed  the  micrococci  in 
the  blood  and  invading  the  tissues,  exactly  as  had  been 
already  obtained  by  the  employment  of  the  pus  of  acute 
abscesses." 

This  is   an  extremely  interesting  experiment, 


BACTERIA  Itf  SURGICAL  LESIONS.  455 

but  Ogston  is  evidently  mistaken  in  ascribing  the 
contradictory  results  at  first  obtained  to  the  fact 
that  the  micrococcus  in  question  is  anaerobic ;  for 
while  this  is  true,  and  it  can  doubtless  grow  in  the 
absence  of  oxygen,  the  writer  has  found  no  diffi- 
culty in  cultivating  it  through  successive  gener- 
ations, in  the  culture-flasks  described  on  page  177, 
in  bouillon  made  from  the  flesh  of  a  rabbit  or  of  a 
chicken,  and  in  the  presence  of  atmospheric  air, 
with  which  these  flasks  are  two-thirds  filled  when 
prepared  in  the  manner  indicated.  Thus,  in  my 
experiments  upon  the  germicide  power  of  various 
therapeutic  agents,  a  pure-culture  of  this  micro- 
coccus  was  maintained  through  many  successive 
generations,  culture  No.  1  having  been  inoculated 
with  a  drop  of  pus  from  a  whitlow,  obtained  at  the 
instant  of  its  escape  from  a  deep  incision.  The 
true  explanation  of  the  contradictory  results  ob- 
tained by  Ogston  is  doubtless  that  given  by  Cheyne, 
viz. :  that  when  no  development  occurred  in  cul- 
ture-solutions inoculated  with  the  pus  of  acute 
abscesses,  it  was  because  the  micrococci  were 
already  dead.  Wernich  has  shown  that  during 
the  multiplication  of  various  bacterial  organisms 
in  a  limited  amount  of  nutritive  pabulum,  chemical 
products  are  evolved  fatal  to  the  vitality  of  these 
organisms. 

In  conclusion,  the  writer  would  suggest  that 
those  who  desire  to  make  themselves  familiar  with 
the  organisms  to  which  a  pathogenic  role  has  been 


456  BACTERIA  IN  SURGICAL  LESIONS. 

ascribed,  and  with  the  technique  relating  to  their 
recognition,  cultivation,  etc.,  will  do  well  to  com- 
mence with  this  micrococcus  of  pus,  a  pure  culture 
of  which  may  be  easily  obtained  in  the  manner 
heretofore  indicated. 


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INDEX. 


ABSCESSES,  bacteria  in,  449. 
Acetic  acid,  antiseptic  action  of,  215. 
Acetic  ferment,  83. 
Aerobies,  116. 
Aeroscopes,  200. 

Alcohol,  germicide  power  of,  215. 
Algae,  bacteria  classed  with,  56. 
Aluminium  acetate,  216. 
Aluminium  chloride,  216. 
Ammonia,  does  not  dissolve    bac- 
teria, 54. 

germicide  power  of,  216. 

source  of,  149. 
Anaerobies,  116. 
Anthrax,  265. 

bacillus  of,  270. 

spores  of,  270. 
Aqueous  humor  as  a  culture-fluid, 

165. 
Aromatic  products  of  decomposition, 

216. 

Arsenious  acid,  216. 
Atmospheric  bacteria,  collection  of, 

197. 
Attenuation  of  virus  : 

method  of  Pasteur,  202. 

of  Toussaint,  204. 

of  Chauveau,  205. 

by  intravenous  injection,  206. 

by  chemical  reagents,  206. 

BACILLUS,  87. 
B.  anthracis,  88. 

development  of,  from  B.  subti- 
lis  (?),  253. 


Bacillus  malarise,  319. 

action  of  quinine  upon,  327. 

in  blood  of  man,  320. 
Bacillus  of  leprosy,  332. 

of  malignant  oedema,  336. 

of  tuberculosis,  391. 

of  typhoid  fever,  408. 
B.  amylobacter,  88. 
B.  des  infusions,  90. 
B.  du  levain,  89. 
B.  du  vin  tourne,  90. 
B.  glaireuse,  90. 
B.  intestinal,  89. 
B.  ruber,  89. 
B.  subtilis,  87. 
B.  utilis,  89. 

Bacteria  in  surgical  lesions,  442. 
Bacterium,  80. 

genus  established  by  Davaine, 

18. 

B.  seruginosum,  85. 
B.  catenula,  82. 
B.  cyaneum,  73. 
B.  lineola,  81. 
B.  littoreum,  81. 
B.  luteum,  73. 
B.  prodigiosum,  73. 
B.  punctum,  82. 
B.  termo,  81. 
B.  sulphuratum,  86. 
B.  violaceum,  74. 
B.  xanthinum,  85. 
Bacterio-purpurine,  38. 
Bastian,  views  and  experiments  of, 
103. 


494 


INDEX. 


Baumgarten,    method    of    staining 

tubercle  bacilli,  191. 
Beggiatoa,  91. 
B.  alba,  91. 
B.  arachnoidea,  91. 
B.  leptomitiformis,  91. 
B.  minima,  91. 
B.  mirabilis,  91. 
B.  uivea,  91. 
Beuzoic  acid,    antiseptic  value  of, 

217. 

Bert,  experiments  of,  269. 
Billrotb,  views  of,  22. 
Blood,  normal,  free    from  bacteria, 

108,  261. 

method  of  obtaining,  161. 
Blood-serum  as  a  culture-medium, 

162. 

method  of  sterilizing,  163. 
Bockhart,  experiments  of,  311. 
Bokai,  experiments  of,  310. 
Boric  acid,  antiseptic  value  of,  122, 

217. 
Bromine,  germicide  power  of,  218. 

CAMPHOR,  antiseptic  value  of,  218. 

Carbolic  acid,  action  of,  upon  bac- 
teria, 122,  219. 

Carbon,  how  obtained  by  bacteria, 
113. 

Carbonic  acid,  action  of,  upon  bac- 
teria, 122. 

Cell-membrane  of  bacteria,  35. 

Cerebro-spinal  meningitis,  284. 

Ceri,  investigations  of,  326. 

Characters,  generic  and  specific,  60. 

Charbon,  265. 

Charbon  symptomatiqne,  280. 

Cheyne,  experiments  of,  398. 

Chlorine,  germicide  value  of,  221. 

Chloroform,  action  of,  upon  bacte- 
ria, 122,  220. 

Chlorophyll,  bacteria   destitute  of, 
56. 

Cholera,  285. 

Cholera  of  fowls,  288. 

Chromic  acid,  221. 
S,  72. 


Cilia,  described  by  Ehrenberg,  39. 

extract  from  paper  of  Dallinger 
and  Drysdale  describing,  41. 

seen  by  various  authors,  39. 
Cladrothrix,  97. 
Cl.  dichotoma,  97. 
Classification  of  Billroth,  23. 

Bory  de  Saint- Vincent,  15. 

Cohn,  65. 

Davaine,  18. 

Dujardin,  17. 

Ehrenberg,  16. 

Hoffman,  20. 

0.  F.  Miiller,  14. 

Nageli,  57. 

Sachs,  57. 

generic    and    specific    charac- 
ters, 59: 

Claxton,  experiments  of,  370. 
Coccobacteria    septica   of   Billroth, 

22. 
Cold,  effects  of,  upon  the  bacteria, 

120. 

Color  of  the  bacteria,  31. 
Colored  bacteria,  where  found,  32. 
Compressed  air,  action  of,  upon  the 

bacteria,  121. 

Coze  and  Feltz,  experiments  of,  349. 
Creosote,  222. 
Culture  flasks,  171,  177. 
Culture-fluid  of  Cohn,  113. 

Pasteur,  112. 

Mayer,  113. 
Culture-fluids,  natural,  161. 

artificial,  167. 

sterilization  of,  168. 
Culture  oven,  180. 
Culture  medium,  solid,  158. 
Cupric  sulphate,  222. 

DALLINGER  and  Drysdale,  extract 
from  paper  of,  on  "  The  Ex- 
istence of  Flagella  in  B. 
Termo,"  41. 

Dnviiiix1,  fl;issilir;ition  of,  18. 

Di -Illation  of  bacteria,  13. 

Detmobftcttiift,  86. 

Dimensions  of  the  bacteria,  29. 


INDEX. 


495 


Diphtheria,  257,  291. 
Diphtheria  of  fowls,  297. 
Dissemination  of  the  bacteria,  103. 

in  air,  1 03. 

in  the  human  organism,  107. 

in  water,  106. 

Distinction    between    animals   and 
vegetables,  53. 

of  bacteria  from  inorganic  sub- 
stances, 49. 
Dujardin,  classification  of,  17. 

EHRLICH'S  method  of  staining  tuber- 
cle bacilli,  191. 
Erysipelas,  286. 
Ether,  germicide  value  of,  222. 
Eucalyptol,  germicide  value  of,  222. 

FAT  granules  in  yellow-fever  blood, 
425. 

resemblance  of,   to  micrococci, 

51. 

Fehleisen,  experiments  of,  286. 
Fermentation,  acetic,  139. 

ammoniacal,  of  urine,  142. 

butyric,  145. 

lactic,  144. 

viscous,  146. 
Fermentations,  role  of  bacteiia  in, 

137. 

Ferri  chloridi  tinct.,  223. 
Ferric  sulphate,  222. 
Fish,  disease  of,  due  to  bacteria,  299. 
Forms  of  the  bacteria,  29. 
Fungi,  bacteria  classed  with,  56. 

GERMICIDES,  definition  of,  209. 
Gibbs'  method  of  staining  tubercle 

•Hi,  192. 
Glanders,  2 
Gliabacterin,  45. 
Gliacoccos,  4.".. 
Gonocoivus  of  Xeisser,  301. 
Gonorrbrca,  301. 
Grocers'  Company,  prize  offered  by, 

413. 
Grouping,  different  modes  of,  43. 


X,  investigations  of,  331. 
Heat,  germicide  power  of,  223. 
Heterogenesis,  102. 
Hoffman,  memoir  of,  20. 
Hospital  gangrene,  probably  due  to 

bacteria,  256. 
Hydrochloric  acid,  224. 
Hydrophobia,  314. 

INFECTIOUS  pneumonia,  342. 
Intermittent  fever,  317. 

experiments  relating  to,  323. 
Iodine,  germicide  value  of,  225. 

KLEBS,  erperiments  of,  relating  to 
intermittent  fever,  319. 

Koch,  experiments  of,  relating  to 
tuberculosis,  387. 

LAVERAN,  investigations  of,  relating 
to  intermittent  fever,  329. 

Leprosy,  331. 

Leptothrix,  90. 

L.  brevissima,  90. 

L.  croespitosa,  90. 

L.  parasitica,  90. 

L.  pusilla,  90. 

L.  radians,  90. 

L.  rigidula,  90. 

L.  spissa,  90. 

Leptothrix  form  of  grouping  of  the 
bacteria,  43. 

Lister's  culture  apparatus,  175. 

MALIGNANT  oedema,  336. 

Measles,  340. 

Mercuric  bichloride,  germicide  value 

of,  225. 

Microbacteria,  65,  80. 
Micrococcus,  72. 
M.  aurantiacus,  73. 
M.  bombycis,  76. 
M.  Candidas,  74. 
M.  chlorinus,  75. 
M.  crepusculum,  75. 
M.  cyaneus,  73. 
M.  diphtheriticus,  76,  292. 
M.  fulvus,  74. 


496 


INDEX. 


Micrococcus  luteus,  73. 
M.  of  epidemic  diarrhoea,  77. 
M.  of  exanthematous  typhus,  78. 
M.  of  glanders,  78. 
M.  of  intestinal  typhus,  78. 
M.  of  pyaemia  of  rabbits,  344. 
M.  of  rugeola,  77. 
M.  of  scarlatina,  77. 
M.  of  septicaemia  of  rabbit,  359. 
M.  of  stringy  wine,  75. 
M.  of  syphilis,  78. 
.M.  of  the  variola  of  animals,  77. 
M.  prodigiosus,  73. 
M.  septicus,  76. 
M.  ureae,  75. 
M.  vaccinse,  76,  412. 
M.  of  variola,  441. 
M.  violaceus,  74. 
Micrococci  in  measles,  341. 

in  pus,  304. 

in  gonorrhceal  pus,  301. 

in  erysipelas,  286. 

in  wounds  treated  aseptically, 
444. 

in  acute  abscesses,  447. 
Microsphaera  vaccinae,  76. 
Microsporon  septicus,  76. 
Microzyma  bombycis,  76. 
Milk  as  a  culture  fluid,  163. 
Milk  sickness,  339. 
Miltzbrand,  265. 
Miquel,  experiments  of,  104. 
Monas  crepusculum,  75. 
M.  gracilis,  79. 
M.  Okenii,  79. 
M.  prodigiosa,  73. 
M.  pulmonale,  Klebs,  342. 
M.  tenno,  81. 
M.  vinosa,  79. 
M.  Warmingii,  79. 
Movement,  brownien,  33. 

cause  of,  34. 

of  two  kinds,  32. 

Miillor,  0.  F.,  classification  of,  14. 
Multiplication,  rapidity  of,  125. 
Mycoderma,  form  of,  45. 
1C.  acfti,  83,  140. 
M.  vini,  141. 


Myconostoc,  96. 
M.  gregarium,  97. 

NAGELI,  classification  of,  57. 
Nitrification,  role  of  bacteria  in,  149. 
Nitrous  acid,  226. 

Nitrogen,  how  obtained  by  the  bac- 
teria, 112. 
Nutrition  of  the  bacteria,  111. 

OGSTON,  experiments  of,  449,  454. 
Oil  of  mustard,  226. 
Oil  of  turpentine,  226. 
Ophidomonas  sanguinea,  80. 
Origin  of  the  bacteria,  101. 
Oscillaria  malariae  of  Laverau,  329. 
Osmic  acid,  226. 
Oxalic  acid,  226. 
Oxygen,  r61e  of,  115. 

germicide  power  of,  227. 
Ozone,  action  of,  upon  the  bacteria, 
121. 

germicide  power  of,  227. 

PALMELLA  prodigiosa,  73. 

Panum,  experiments  of,  262. 

Pasteur,  experiments  relating  to  hy- 
drophobia, 314. 

Pathogenes,  75. 

Pathogenic    bacteria,    development 
of,  252. 

Penicillium,    in    blood    of    yellow 
fever,  426. 

Pernicious  fever,  325. 

Petalobacteria,  46. 

Petalococcos,  46. 

Photographing  bacteria,  194. 

Picric  acid,  227. 

Pigmentary  bacteria,  72. 

Place  of  the  bacteria  in  vegetable 
series,  55. 

Pleuro-pneumonia,  341. 

Polymorphism,  133. 

Position  of  the  bacteria,  48. 

Potash,  germicide  value  of,  227. 

Potassium  arsrnite,  228. 
chlorate,  228. 
iodide,  228. 


INDEX. 


497 


Potassium  nitrate,  228. 
permanganate,  228. 
Protective  inoculations  in  anthrax, 

in  septicaemia,  372. 

modus  operand  i,  Pasteur's  ex- 
planation of,  242. 

Author's  explanation,  246. 
Protoplasm,  currents  in,  37. 

granules  in,  37. 

of  the  bacteria,  36. 
Pseudobacteria,  50. 
Ptomaines,  257. 
Pulverulent  precipitate,   consisting 

of  bacteria,  46. 
Pure  cultures,  methods  of  obtaining: 

Lister's  method,  156. 

Koch's  method,  157. 
Pus,  bacteria  in,  111,  307,  444. 
Putrefaction,  role  of  bacteria  in,  148. 
Pyaemia  in  rabbits,  343. 
Pyrogallic  acid,  229. 

QUININE,  germicide  value  of,  229, 
326. 

RECOGNITION  of  bacteria,  184. 
Relapsing  fever,  346. 

inoculation  experiments  relat- 
ing to,  347. 
Reproduction  of  the  bacteria,  123. 

by  fission,  123. 

by  spores,  126. 

Respiration  of  the  bacteria,  111. 
Rhabdomonas  rosea,  80. 
Rosenberger,  experiments  of,  259. 

SACCHAROMYCETES,  57. 
Sachs,  classification  of,  57. 
Salicylic  acid,  229. 
Saliva,  micrococcus  of,  359. 
Sarcina,  96. 
Scarlet  fever,  349. 

in  animals,  350. 
Schizomycetes,  Nageli,  57. 
Schizophytes,  Cohn,  66. 
Sepsin,  258. 
Septic  toxaemia,  259. 


Septicaemia  in  mice,  351. 
Septicaemia  in  rabbits,  355. 

etiology  of,  356. 

pathology  of,  360. 
Soda,  germicide  value  of,  230. 
Sodium  biborate,  231. 
Sodium  chloride,  231. 
Sodium  hyposulphate,  232. 
Sodium  salicylate,  232. 
Sodium  sulphite,  232. 
Species,   physiological,   of  Pasteur, 
63. 

value  of,  61. 
Spherobacteria,  71. 
Spirillum,  94. 
S.  attenuatum,  96. 
S.  Rosenbergii,  96. 
S.  rufum,  94. 
S.  tenue,  94. 
S.  undula,  94. 
S.  violaceum,  96. 
S.  volutans,  94. 
Spirobacteria,  91. 
Spirochaete,  93. 
S.  gigantea,  93. 
S.  Obermeieri,  93. 
S.  plicatilis,  93. 
Spirochsete  Obermeieri,  347. 
Spiromonas  Cohnii,  80. 
Sporangia,  130. 
Spores,  development  of,  128. 

germination  of,  131. 
Spores  of  B.  anthracis,  270. 
Spreading  abscess  in  rabbits,  376. 
Staining  bacteria,  186. 
Starch,  in  Bacillus  amylobacter,  39. 
Sterilization  of  culture-fluids,   168, 

172. 

Structure  of  the  bacteria,  35. 
Sulphur,     contained     in     bacteria, 

33. 

Sulphuretted  hydrogen,  234. 
Sulphuric  acid,  233. 
Sulphurous  acid,  233. 
Swine  plague,  378. 
Symptomatic  anthrax,  280. 
Syphilis,  380. 
Syphilitic  organisms,  381. 


498 


INDEX. 


TAXNIC  acid,  234. 

Temperature,    action  of,  upon   bac- 
teria, 118. 
Thermal  death- point  of  bacteria,  119. 

of  B.  anthracis,  270. 

of  M.  of  fowl  cholera,  289. 

of  septic  inicrococcus,  364. 
Thermostat  for  gas,  181. 

electro-magnetic,  183. 
Thymol,  234. 

Tommasi-Crudeli,  experiments  re- 
lating to  intermittent  fever, 
319,  325. 

Torula  form  of  bacteria,  43. 
Tubercle  bacillus,  386. 

methods  of  staining,  190. 

morphology  of,  393. 
Tubercles  without  bacilli,  390. 
Tuberculosis,  384. 
Typhoid  bacilli  of  Klebs,  407. 

of  Eberth,  409. 
Typhoid  fever,  400. 

lower  animals  not  subject  to, 
403. 

ULCERATIVE  endocarditis,  411. 
Urine  as  a  culture-fluid,  164. 

method  of  obtaining  free  from 
bacteria,  165. 

VARIOLA,  411. 
Variola  of  pigeons,  413. 
Venom  of  serpents,  261. 


Vibrio,  92. 
V.  bacillus,  89. 
V.  lactic,  83. 
V.  lineola,  81. 
V.  prolifer,  94. 
V.  rugula,  92. 
V.  serpens,  93. 
V.  subtilis,  87. 
V.  syncyanus,  85. 
V.  synxanthus,  85. 
V.  tartaric  right,  83. 
V.  tremulans,  81. 

Vibrioniens,    definition   of,   Ehren- 
berg,  16. 

WATER,  examination  of,  201. 

Whooping  cough,  415. 

Wood,  H.  C.,  experiments  of,  295. 

YELLOW  fever,  417. 

blood  of,  422,  108. 
Yellow-fever    commission,    extracts 

from  report  of,  421. 
Yellow-fever  germ  of  Carmona,  432. 

of  Freire,  439. 

ZINC  chloride,  234. 
Zinc  sulphate,  235. 
Zoogloea  form  of  grouping  of  the 

bacteria,  44. 
Zooglcea,     genus     established      by 

Cohn,  21. 
Zymogenes,  75. 


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